Merrill LynchHealth Services Investor

Conference November 29, 2005

2

Statements included in this presentation or in the oral comments made as part of this presentation may contain forward-looking statements, including but not limited to statements of the Company’s plans, objectives, expectations or intentions, that involve risk and uncertainties.

The Company’s actual results may differ significantly from those projected or suggested in any forward-looking statement due to a variety of factors, which are discussed in detail in the Company’s filings with the Securities and Exchange Commission.

Forward-Looking Statements

3

Today’s Challenging Environment:

Keeping the Prescription Drug Benefit Off the

Endangered List

% Increase in Unmanaged PMPY Cost

11.311.211.612.011.810.6

15.5

18.5

0

4

8

12

16

20

2002 2003 2004 2005 2006 2007 2008 2009

Perc

ent

Rx's Cost

Unmanaged Prescription Drug Trend

Plan sponsors will likely increase the use of PBM tools to manage drug spend

Source: 2004 Drug Trend Report

5

Our Value Proposition: Complete Alignment

To reduce pharmacy costs, without compromise to health

outcomes, while maximizing patient satisfaction

6

More Number of Drugs Fewer

Ben

efi

t O

pti

on

s

Impact on Client

Impact on Patient

Impact on ESI

Lower drug cost

More choice

Lower co payment

More choice

Higher Profit/Rx

More Flexibility

Alignment –Formulary Management

Therapy Class

We Provide Flexible Formulary Management

1. Select number of drugs in therapy class 2. Determine formulary control 3. Drive towards lowest overall cost

# ofdrugs

# ofdrugs

# ofdrugs

Open

DifferentialCo-pay

ClosedLowestOverall

Cost

7

Alignment - Retail Network Management

States

Available Pharmaci

es

Most Inclusive Network

Most Restrictiv

e Network

TRICARE Access

Minimum

CA 5,644 5,071 3,881 283NY 4,444 4,224 1,829 300TX 4,236 3,821 1,827 579FL 4,020 3,670 1,966 469PA 2,970 2,825 1,687 432

Greater Management

•Higher Profit/Rx•More Flexibility

•Lower co payment•More choice

•Lower drug cost•More choice

•Impact on ESI•Impact on Patient•Impact on Client

Higher Profit/RxLower co paymentLower drug cost

Impact on ESIImpact on PatientImpact on Client

8

Impact on Client

Impact on Patient

Impact on ESI

Lower drug cost

Lower co payment

Higher Profit/Rx

Alignment – Clinical Programs

4.5

13.0

0

2

4

6

8

10

12

14

Mil

lio

ns

Q1 2003 Q4 2004

Members in Step Therapy Programs

Clients using step therapy realize on average a

2 percentage point increase in generic utilization

Plan Designs Encourage Greater Use of

Generics and Preferred Low-cost Brands

9

Alignment – Home Delivery

Impact on Client

Impact on Patient

Impact on ESI

Lower drug cost

Choice

Lower co paymentChoice

Higher profit/Rx

We Offer Highly Efficient, Cost-effective

Home Delivery

10

16.4%

18.5%

22.6%

20.2%

17.2%

13.8%

15.8%

13.1%0

100

200

300

400

500

600

1996 1997 1998 1999 2000 2001 2002 2003 2004

Ad

just

ed C

laim

s* (

mill

ion

s)

13.0%14.0%15.0%16.0%17.0%18.0%19.0%20.0%21.0%22.0%23.0%24.0%

% m

ail p

enet

ratio

n

Total Adjusted Claims Home Delivery Penetration

* Represents network claims plus 3 times home delivery claims –home delivery claims are 90 days vs. 30 days in the network.

Excludes UHC claims

D IVERSIFIED®

Increased home delivery penetration

Home Delivery Helps Manage the Cost of Maintenance Drugs

Alignment – Growing Demand for Home Delivery

11

Alignment – Generic Utilization

Generic Utilization Rate

38%40%42%44%46%48%50%52%54%56%

Q102

Q202

Q302

Q402

Q103

Q203

Q303

Q403

Q104

Q204

Q304

Q404

Q105

Q205

Q305

ESI PBM B PBM C

Impact on Client

Impact on Patient

Impact on ESI

Lowest drug cost

Lowest co payment

Highest profit/Rx

Source: From public filings

Express Scripts Leads in Generic Utilization

12

$10.3

$11.3

$10.4 $10.4

$9.8

$7

$8

$9

$10

$11

$12

$ -

bil

lio

ns

2005 2006 2007 2008 2009

U.S. Sales for Brand Products with Patent Expirations From 2005-2009

ESI Analysis

Represents

over 20%

of 2004

branded

drug sales

Our Clients and Members Will Benefit From a Growing Generic Opportunity

Alignment – Growing Generic Opportunity

Alingnment – Specialty Pharmacy

Sources:IMS Data through November 2004Wall Street Equity Research, 2004CMS National Healthcare Expenditure Projection: 2003 – 2013Data on file: CuraScript.

2004 Total Outpatient Pharmacy Spend $190 Billion

2008 Projected Outpatient Pharmacy Spend $283 Billion

26%26%18%18%

Traditional SpendTraditional Spend$210 Billion$210 Billion

Specialty SpendSpecialty Spend$73 Billion$73 Billion

Specialty SpendSpecialty Spend$35 Billion$35 Billion

Traditional SpendTraditional Spend$155 Billion$155 Billion

Impact on Client

Impact on Patient

Impact on ESI

Lower drug cost

Lower co payment

Higher profit/Rx

Improved reporting

Improved quality of

care

Higher client

satisfaction

Clients are Seeking Solutions for High-cost

Specialty Drugs

Express Scripts’ specialty penetration has increased from 2% to 30%

in the first 5.5 quarters of our CuraScript acquisition.

Per

cent

age

of P

lan

Cos

ts

Source: Express Scripts Analysis.

82%

73%70% 69%

66%63%

60%

2%

17%20%

25%30%

34%

16%

6%

14%

7%9%11%13%13%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

Q1 2004 Q2 2004 Q3 2004 Q4 2004 Q1 2005 Q2 2005 Q3 2005

RetailCuraScriptHome Delivery

CuraScript Penetration intoExpress Scripts

Priority Acquisition - Strategic Rationale Creates one of the largest specialty franchises in the U.S.

– $3+ billion annual specialty revenues

– One of the fastest growing sectors in healthcare

– Sector remains fragmented and market structure continues to emerge (greenfield opportunities)

Fills key therapy classes within CuraScript portfolio – “one-stop shopping for clients”

– Infertility (number one fertility franchise)

– Pulmonary Fibrosis

– Pulmonary Hypertension

– Home Infusion Offers additional capabilities

– Specialty distribution capabilities

– Supply chain services Leverages PBM core competencies (payor and manufacturer relationships, mail

order pharmacies, clinical and trend management expertise)

– Synergy potential

– Increased value proposition for clients (single vendor, integrated reporting)

16

What Are the Savings?

Availability of Proven PBM Cost Management Tools Will Produce 20%–25% Savings (CBO)

Paid byCash Customer

at Pharmacy

Retail, Clinical.Formulary

And RebateSavings 24%

Home Delivery

Savings 6%

Paid byExpress ScriptsClients

Total Savings 30%

COST

Retail Pharmacy Cash Price

Express Scripts Client Savings

Express Scripts Client Costs

17

Alignment – A Win-Win-Win Proposition

Retail Non-pref. Brand

Retail Pref.

BrandGenerics

Mail Pharma

cy

Increased Savings

Opportunities:

Client

Member

Increased

Profit

Opportunities:

Express Scripts

Moving to preferred brands, home delivery and generics

We make money by saving clients and members money

Moving to preferred brands, home delivery and generics

Moving to preferred brands, home delivery and generics

18

We Deliver Against Client and Patient Expectations:

To make the use of prescription drugs safer and

more affordable

19

Client/Patient Focus

Commercial26%

Canada10%

Managed Care39%

Public Sector25%

By membership

Health Plan Sponsors Recognize Express Scripts Single

Focus on Making Prescription Drugs More Affordable

Why Express Scripts?• Alignment With

Clients• Generics• Specialty

20

2006 Upsell Pipeline is Strong

• Significant potential to continue to manage client trends in key product categories

• New products continue to be developed and rolled out

• Strong track record of success

10,000

('000

Liv

es)

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

Hom

e Del

iver

y

Gener

ic E

nfor

cem

ent

Nar

rowin

g Fo

rmul

arie

s

New

Clin

ical

Pro

duct

s

Spec

ialty

/Cur

aScr

ipt

Thre

e Ti

er

Sold Weighted Pipeline

21

Client Satisfaction Steadily Improving

• Service and satisfaction metrics have increased consistently quarter over quarter since 2003 with an early spike in 2005

Exceed60%

65%

70%

75%

80%

85%

90%

95%

100%

ESI PerformanceExpectations

Likelihood toRecommend

Likelihood toRenew

2003

2004

1q05

22

Our Financial Results

Express Scripts has demonstrated a proven track

record

23

Q3 2005 Highlights

– Adjusted EPS of $0.67*, up 34% from $0.50* last year

– Cash flow from operations of $214.6 M vs. $150.0 M last year

• Repurchased 4.0 million shares for $219.9 million

– Generic drugs were 55% of total prescriptions vs. 51% last year

– Gross profit of $293.2 M, up 25% • Gross profit per adjusted claim was $2.13, up 20%• EBITDA per adjusted claim was $1.32, up 19%

– Raised EPS guidance for 2005

– Provided 2006 EPS guidance of $3.10 to $3.22*Excludes prior period tax benefit of $0.01 in Q3 2005 and non recurring charge of $0.10 for legal defense costs in Q3 2004 – reconciliation of reported EPS to adjusted EPS is included in Table 4 of the 3Q 2005 earnings release

24

Quality of Earnings

$0.00

$0.20

$0.40

$0.60

$0.80

$1.00

$1.20

Q1'01

Q2'01

Q3'01

Q4'01

Q1'02

Q2'02

Q3'02

Q4'02

Q1'03

Q2'03

Q3'03

Q4'03

Q1'04

Q2'04

Q3'04

Q4'04

Q1'05

Q2'05

Q3'05

Pe

r s

ha

re

EPS Free cash flow per share*

(1) Reflects a $70-$75 million reduction in Q2 2003 due to one-time impact of implementing a new wholesale purchase agreement

(2) Excludes a $0.04 per share charge for the early retirement of debt(3) Excludes a $0.10 charge to increase legal reserves for the cost of defense.(4) Excludes an $0.08 and $0.01 prior year tax benefit in Q2 and Q3, respectively

(1)(1)

(2)(2)

* Reflects a 12-month moving average of free cash flow (cash from operations less CapX)

(3)(3)(4)(4)

(4)(4)

25

Components of EPS Growth — 2004

0%

5%

10%

15%

20%

25%

Rx Growth EBITDA/ Rx Growth Cap Structure/ Other

* Excluding $25 million charge to increase legal reserves for the cost of defense and $5.5 million termination payment received

6%6%

7%7%

8%8%

2004

-5%

0%

5%

10%

15%

20%

1999 2000 2001 2002 2003 2004 2005*

Adju

sted C

laim

s G

row

th

Express Scripts Caremark Medco

Major PBM Prescription Growth

Note: Rx growth for Medco, Caremark reflect as configured today* YTD 9-30-05

27

Claims Volume Vs. EPS Growth

0%

5%

10%

15%

20%

25%

30%

35%

40%

Q3 '04 Q4 '04 Q1 '05 Q2 '05 Q3 '05

EPS growth Adj. claim growth

(1) Excludes a $0.10 charge to increase legal reserves (4) Reflects the June 1st anniversary of the DoD retail contract

(2) Excludes an $0.08 prior year tax benefit(3) Excludes a $0.01 prior year tax benefit

(2)(2)(3)(3)

(1)(1)

Expanding Margins Supports Strong EPS Growth on More Modest Claims Growth

(4)(4)

Profits Per Claim Growth

$1.32

$1.19

$0.81

$0.88

$1.03 $1.05

$1.11$1.12

$0.60

$0.80

$1.00

$1.20

$1.40

2000 2001 2002 2003 2004** Q1 '05 Q2 '05 Q3 '05

EBITDA* per adjusted claim

* A reconciliation of EBITDA to net income and to net cash provided by operating activities can be found in the Investor Relations

section of Express Scripts’ Web site, www.express-scripts.com under Presentations.

** Excluding $25 million charge to increase legal reserves for the cost of defense and $5.5 million termination payment received.

Pricing can be lowered as clients tighten formulary compliance, increase home delivery, utilize generics and restrict retail networks. These changes result in lower prices to our clients and greater profits to Express Scripts.

11% CAGR

Gross Profit* / SG&A* / EBITDA per Adj. Rx

Future EBITDA per Adj. Rx Must Come From Gross Profit per Adj. Rx

* Before depreciation and amortization** Excluding $25 million charge to increase legal reserves for the cost of defense and $5.5 million termination payment received. Source: Express Scripts Analysis.

$1.32

$2.20

$0.78 $0.83$0.90

$0.80 $0.74$0.82 $0.83 $0.88

$1.12 $1.11$1.05$1.03

$0.88$0.81

$1.19

$1.59$1.71

$1.93$1.85

$1.86 $1.93$2.02

$0.50

$0.70

$0.90

$1.10

$1.30

$1.50

$1.70

$1.90

$2.10

2000 2001 2002 2003 2004** Q1 2005 Q2 2005 Q3 2005

30

Focus on Return on Invested Capital (ROIC)

Express Scripts ROIC*

0%2%

4%6%

8%10%

12%14%

16%18%

20%

2000

2001

2002

2003

2004

**

ROIC is our Preferred Performance Metric

* Reflects operating income less tax divided by average invested capital, which consists of stockholder’s equity, plus interest

bearing liabilities plus long-term deferred income taxes, net. ** Excludes $25 million charge to increase legal reserves for the cost of defense and 5.5 million termination payment received

31

Why Express Scripts? Industry-Leading ROIC

Comparison of Peer Group ROIC - 2004

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

Expr

ess

Scri

pts

Cig

na

Wal

gree

ns

Car

emar

k

Aet

na

CVS

Med

co

Wel

lpoi

nt

We Lead Our Peer Group in ROIC Performance

Source: Express Scripts Analysis

32

Peer Group Total Return YTD 11-18-05

ESI’s 108% YTD return is more than 3.5 times our peer group

52.0%

39.8% 38.5%

3.0%

20.1%

26.6% 23.5%34.1% 27.3%

107.9%

0%

20%

40%

60%

80%

100%

Peer group avg.

30.2%

33

S&P Total Return – YTD 11-18-05

46

140

186

89

29

5 2 30

25

50

75

100

125

150

175

200

Total Return

# of

Com

pani

es

Only 1 company in the S&P 500 exceeded ESI’s

total return to stockholders of 107.9% YTD thru 11-18-05

Note: Returns reflect stock price increase plus dividend yield

34

Our Value Proposition Will Continue to Drive Growth

• Making the use of drugs safer and more affordable is more important than ever

• Plan sponsors will increasingly deploy our tools

• Express Scripts is well-positioned for sustainable growth

• Strong market fundamentals/new business opportunities • Increased use of home delivery and generic drugs• Growth in management of specialty pharmacy• Productivity and capital structure improvements

• We have taken a different approach• Alignment -- we make money by saving our clients money

• Strategic acquisitions have enhanced our value proposition