Lehman Brothers 8th Annual Global Healthcare Conference April 1, 2005

1. Express Scripts Aligning Interests Lehman Brothers 8th Annual Global Healthcare Conference April 1, 2005

2. Forward-Looking Statements 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.

3. Our Interests are Aligned with Clients and Patients: To make the use of prescription drugs safer and more affordable

4. We Evaluate Drugs for Price and Value 1. Determine cost per Rx (AWP) Alignment – Formulary Management Ensure Clinical Quality at Lowest Cost Relative clinical value Drug B Drug A Drug D Drug C $0 $20 $40 $60 $80 $100 $120 Cost for 30-day supply

5. We Evaluate Drugs for Price and Value 1. Determine cost per Rx (AWP) 2. Evaluate relative clinical value Alignment – Formulary Management Ensure Clinical Quality at Lowest Cost Drug D Drug A Drug B Relative clinical value Drug C $0 $20 $40 $60 $80 $100 $120 Cost for 30-day supply

6. We Evaluate Drugs for Price and Value 1. Determine cost per Rx (AWP) 2. Evaluate relative clinical value 3. Account for market share Alignment – Formulary Management Ensure Clinical Quality at Lowest Cost Drug A Drug D Drug B Relative clinical value Drug C $0 $20 $40 $60 $80 $100 $120 Cost for 30-day supply

7. We Evaluate Drugs for Price and Value 1. Determine cost per Rx (AWP) 2. Evaluate relative clinical value 3. Account for market share 4. Select formulary products 5. Determine effects of rebate Alignment – Formulary Management Ensure Clinical Quality at Lowest Cost Drug A Drug D Drug B Relative clinical value Drug C $0 $20 $40 $60 $80 $100 $120 Cost for 30-day supply

8. Alignment – Clinical Programs Plan Designs Encourage Greater Use of Generics and Preferred Low-cost Brands Clients using step therapy realize on average a 2 percentage point increase in generic utilization

9. More Number of Drugs Fewer Alignment – Supply Chain Management Therapy Class We Provide Flexible Management of the Supply Chain 1. Select number of drugs in therapy class # of drugs # of drugs # of drugs # of drugs

10. More Number of Drugs Fewer Benefit Options Alignment – Supply Chain Management Therapy Class We Provide Flexible Management of the Supply Chain 1. Select number of drugs in therapy class 2. Determine formulary control # of drugs # of drugs # of drugs # of drugs Open Differential Co-pay Closed

11. More Number of Drugs Fewer Benefit Options Alignment – Supply Chain Management Therapy Class We Provide Flexible Management of the Supply Chain 1. Select number of drugs in therapy class 2. Determine formulary control 3. Drive towards lowest overall cost # of drugs # of drugs # of drugs # of drugs Open Differential Co-pay Lowest Overall Cost Closed

12. Video of Express Scripts High Volume Mail Pharmacy Alignment – Home Delivery We Offer Highly Efficient, Cost-effective Home Delivery

13. Alignment – Growing Demand for Mail Increased mail penetration * Represents network claims plus 3 times mail claims - mail claims are 90 days vs. 30 days in the network. Excludes UHC claims Home Delivery Helps Manage the Cost of Maintenance Drugs

14. Alignment – Generic Utilization Express Scripts Leads in Generic Utilization Source: From public filings

15. Alignment – Growing Generic Opportunity Represents approximately 18% of 2003 branded drug sales ESI Analysis Our Clients and Members Will Benefit From a Growing Generic Opportunity

16. Oncology $12.6 36% HIV/AIDS 3.4 10% Renal 3.2 9% Hemophilia 1.6 5% Hepatitis C 1.6 5% Transplant 1.5 4% Multiple sclerosis 1.5 4% Rheumatoid arthritis 1.5 4% RSV prophylaxis 0.6 2% Infertility 0.5 1% Growth Hormone 0.5 1% Other 3.5 19% Total $35 100% Alignment – Specialty Pharmacy Billions Specialty Market 2004 Source: ESI Analysis Clients are Seeking Solutions for High-cost Specialty Drugs

17. Alignment -- PBM Tools Work Availability of Proven PBM Cost Management Tools Will Produce Savings of 20 – 25% (CBO)

18. Plan Sponsors Want Value for Their Drug Spend What Do Plan Sponsors Want? Unmanaged Drug Trend • Affordability • Flexibility • Accountability 20% 15% 10% 5% 0% -5% 2006 2007 2008 2001 2002 2003 2004 2005 Source: 2003 ESI Drug Trend Report

19. Managed trend - 2003 ESI Provides Value for Clients’ Drug Spend What Does Express Scripts Provide? Unmanaged Drug Trend • Affordability • Low-cost formulary • Effective clinical programs • Mail pharmacy services • Flexibility • Customized management of the pharmacy benefit • Accountability • Alignment of interests • Transparency 20% 15% 10% 5% 0% -5% 2003 Managed 2001 2002 2003 2003 1 New Tool 2003 2 New Tools Source: 2003 ESI Drug Trend Report

20. Increased Savings Opportunities: Client Member Increased Profit Opportunities: Express Scripts Moving to preferred brands, mail and generics Moving to preferred brands, mail and generics Moving to preferred brands, mail and generics Retail Non-pref. Brand Retail Pref. Brand Mail Pharmacy Generics Alignment – A Win-Win-Win Proposition We make money by saving clients and members money

21. Average Annual Drug Spend Among Medicare Population Source: Actuarial Research Corporation The Medicare Prescription Drug Act will shape the direction of our industry for years to come PBM’s Are Part of the Solution for Medicare Medicare Prescription Drug Act of 2003 • PBM’s are expected to play an important role • Congressional Budget Office estimated PBM’s would save Medicare about 25% • We will review the regulations to evaluate our participation in the program • We will work closely with employers and plans supporting their participation in Part D.

22. Benefits of ePrescribing Medicare Part D Will Advance Important Initiatives Including e- Prescribing

23. We Deliver Against Client and Patient Expectations: To make the use of prescription drugs safer and more affordable

24. Client/Patient Focus • Successful track record in growing membership to over 50 million • Differentiation through flexible formulary, clinical programs and retail network management • New market opportunities – 70 to 100 million unmanaged lives • Medicare • Medicaid • Uninsured By membership Health Plan Sponsors Recognize Express Scripts Single Focus on Making Prescription Drugs More Affordable

25. Case Study: Medium-Sized Employer $1,000 800 600 60% PMPY 40 400 GFR Mbr share 20 0 1999 2000 2001 2002 2003 Generics policy Plan design Clinical/trend programs

26. Case Study: Medium-Sized Employer $1,000 SAVINGS: $250 PMPY 800 600 60% PMPY 40 400 GFR Mbr share 20 0 1999 2000 2001 2002 2003 Generics policy Plan design Clinical/trend programs

27. Express Scripts’ Major Locations –Thru Mid 2004 Bloomington, MN Troy, NY Patient Contact Centers Patient Contact Center Farmington Hills, MI Mail Service Pharmacy Patient Contact Centers E. Hanover, NJ Patient Contact Center St. Louis, MO Harrisburg, PA Corporate Headquarters Patient Contact Center Patient Contact Center Mail Service Pharmacy Mail Service Pharmacy St. Marys, GA Patient Contact Center Albuquerque, NM Patient Contact Center Orlando, FL Mail Service Pharmacy CuraScript Bensalem, PA Mail Service Pharmacy High Vol Mail Services Patient Contact Center Tempe, AZ Patient Contact Center High Vol Mail Services Mail Service Pharmacy

28. Troy, NY Patient Contact Center E. Hanover, NJ Patient Contact Bensalem, PA High Vol Mail Services Patient Contact Center St. Marys, GA Patient Contact Center Albuquerque, NM Albuquerque, NM Patient Contact Center Patient Contact Center Orlando, FL Mail Service Pharmacy CuraScript Express Scripts’ Major Locations –2005 Plan Bloomington, MN Patient Contact Centers Farmington Hills, MI Rx Entry Mail Service Pharmacy Patient Contact Centers Harrisburg, PA St. Louis, MO Patient Contact Center Corporate Headquarters Patient Contact Center Rx Entry Mail Service Pharmacy High Vol. Mail Services High Vol Mail Services Mail Service Pharmacy Tempe, AZ Patient Contact Center High Vol Mail Services Mail Service Pharmacy Mail Pharmacy Services

29. Our Focus on Service is Evident from High Overall Client Satisfaction High Client Satisfaction

30. Our Financial Results Express Scripts has demonstrated a proven track record

31. Financial Overview Q4 2004 Highlights • 4Q EPS $1.07, up 24% from last year • Record cash flow from operations of $193.0 million • Repurchased 2.4 million shares for $176 million • Record mail claims of 10.1 million, up 17% from last year • Generic drugs were 52% of total prescriptions vs. 48% last year • Gross profit up 13%

32. Greater Rx Volumes Have Created Economies of Scale Financial Overview Claims volume growth Network Claims* (Millions) 1992-2004 = 44% CAGR Mail Claims (Millions) 1992-2004 = 40% CAGR * Excludes UHC claims

33. Pricing can be lowered as clients tighten formulary compliance, increase mail, utilize generics and restrict retail networks. These changes result in lower prices to our clients and greater profits to ESI Financial Overview 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 at 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.

34. Financial Overview Quality of earnings (3) (1) (2) Reflects a $70-$75 million reduction in Q2 2003 due to the one-time impact of implementing a new wholesale purchase agreement Excludes a $0.10 per share charge for the early retirement of debt Excludes a $0.20 charge to increase legal reserves for the cost of defense. * Reflects a 12 month moving average of free cash flow (cash from operations less CapX)

35. ROIC is our Preferred Performance Metric Focus on Return on Invested Capital (ROIC) * 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

36. We Lead Our Peer Group in ROIC Performance Industry-Leading ROIC Source: ESI Analysis

37. 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 acquisitionshave enhanced our value proposition

38. Express Scripts Aligning Interests