Lehman Brothers 9th Annual Global Healthcare Conference March 8, 2006

1. Lehman Brothers 9th Annual Global Healthcare Conference March 8, 2006

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. Today’s Challenging Environment: Maintaining Access to Safe and Affordable Drugs

4. Unmanaged Prescription Drug Trend Source: 2004 Drug Trend Report Plan Sponsors Will Likely Increase the Use of PBM Tools to Manage Drug Spend

5. Our Value Proposition: Complete Alignment To reduce pharmacy costs, without compromising health outcomes, while maximizing patient satisfaction

6. High Performance Formulary Restricted Retail Network Exclusive Home Delivery Specialty Pharmacy Step Therapy Generic Utilization Programs 3-tier 2-tier The Art of Trend Management -- Alignment Ability to manage trend Plan sponsor appetite for innovative clinical tools As Plan Sponsors Take Advantage of Our Tools to Better Mange Trend, The Better We Perform

7. $50 $60 $70 $80 Alignment - Building a Formulary • Evaluate relative clinical value Drug A Drug B Relative clinical value Drug C Cost per prescription

8. $50 $60 $70 $80 Alignment - Building a Formulary • Evaluate relative clinical value • Determine net cost Drug A Drug B Relative clinical value Drug C Cost per prescription

9. Most cost effective Drug A Drug B Drug C Alignment - Building a Formulary • Evaluate relative clinical value • Determine net cost • Account for market share A B Relative clinical value C $50 $60 $70 $80 Cost per prescription

10. Most cost effective Drug A A A B B Drug B Drug C Alignment - Building a Formulary • Evaluate relative clinical value • Determine net cost • Account for market share • Account for rebates Relative clinical value C $50 $60 $70 $80 Cost per prescription

11. Most cost effective Most cost effective Drug B Drug A Drug A Drug B Relative clinical value Drug C Drug C $50 $60 $70 $80 Cost per prescription Alignment - Building a Formulary • Evaluate relative clinical value • Determine net cost • Account for market share • Account for rebates • Select formulary products A B Exceptions: * Market dynamics can trump net cost * High Performance Formulary C

12. More Number of Drugs Fewer Benefit Options 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 # of drugs # of drugs # of drugs Open Differential Co-pay Lowest Overall Cost Closed

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

14. Alignment – Growing Generic Opportunity ESI Analysis Our Clients and Members Will Benefit From a Growing Generic Opportunity

15. 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

16. Alignment – Specialty Pharmacy Traditional Spend $210 Billion Specialty Spend $35 Billion 2004 Total Outpatient Pharmacy Spend $190 Billion Specialty Spend $73 Billion 26% 18% 2008 Projected Outpatient Pharmacy Spend $283 Billion Traditional Spend $155 Billion Sources: IMS Data through November 2004 Wall Street Equity Research, 2004 CMS National Healthcare Expenditure Projection: 2003 – 2013 Data on file: CuraScript. Clients are Seeking Solutions for High-cost Specialty Drugs

17. CuraScript Penetration intoExpress Scripts Percentage of Plan Costs Source: Express Scripts Analysis. Express Scripts’ Specialty Penetration Has Increased from 2% to 36% in the First 2 Years of the CuraScript Acquisition.

18. Alignment – Home Delivery We Offer Highly Efficient, Cost-effective Home Delivery

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

20. What Are the Savings? Retail, Clinical. Formulary And Rebate Savings 24% Paid by Cash Customer at Pharmacy Retail Pharmacy Cash Price Home Delivery Savings 6% Express Scripts Client Savings Express Scripts Client Costs C O S T Paid by Express Scripts Clients Total Savings 30% Availability of Proven PBM Cost Management Tools Will Produce 20%–25% Savings (CBO)

21. Increased Savings Opportunities: Client Member Increased Profit Opportunities: Express Scripts Moving to preferred brands, home delivery and generics Moving to preferred brands, home delivery and generics Moving to preferred brands, home delivery 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

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

23. Client/Patient Focus Why Express Scripts? • Alignment With Clients • Trend management tools • Generics • Specialty By membership Health Plan Sponsors Recognize Express Scripts Single Focus on Making Prescription Drugs More Affordable

24. Client Satisfaction continues to improve.. Increases Were Recognized in All Categories With Likelihood to Renew Showing the Largest Increase

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

26. Q4 2005 Highlights • Adjusted EPS of $0.77*, up 45% from $0.53 last year • For 2005, adjusted EPS of $2.60*, up 34% from 2004 • Cash flow from operations of $262 M vs. $193 M last year • For 2005, cash flow of $793 M vs. $496M in 2004 • Gross profit of $364 million, up 38% • Gross profit per adjusted claim was $2.54, up 34% • EBITDA of $220 M, up 42% • EBITDA per adjusted claim was $1.53, up 37% * Reconciliation of reported EPS to adjusted EPS is included in Table 4 of the 4Q 2005 earnings release

27. Quality of Earnings (5) (1) (4) (4) (3) (2) Reflects a $70-$75 million reduction in Q2 2003 due to one-time impact of implementing a new wholesale purchase agreement Excludes a $0.04 per share charge for the early retirement of debt Excludes a $0.10 charge to increase legal reserves for the cost of defense. Excludes an $0.08 and $0.02 prior year tax benefit in Q2 and Q3, respectively Excludes a $0.02 charge for the early retirement of debt * Reflects a 12-month moving average of free cash flow (cash from operations less CapX)

28. Components Of EPS Growth

29. Major PBM Prescription Growth Note: Rx growth for Medco, Caremark reflect as configured today

30. Claims Volume Vs. EPS Growth Expanding Margins Supports Strong EPS Growth on More Modest Claims Growth (5) (3) (2) (1) (4) Excludes a $0.10 charge to increase legal reserves (4) Reflects the June 1st anniversary of the DoD retail contract Excludes an $0.08 prior year tax benefit (5) Excludes a $0.02 charge for early retirement of debt Excludes a $0.02 prior year tax benefit

31. Profits Per Claim Growth EBITDA* per adjusted claim 10% CAGR*** 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. * 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. *** Based on 2005 average EBITDA per adjusted Rx of $1.29

32. Gross Profit* / SG&A* / EBITDA 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. Future EBITDA per Adj. Rx Must Come From Gross Profit per Adj. Rx

33. 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 ROIC is our Preferred Performance Metric

34. Peer Group Total Return - 2005 Peer group avg. 32.4% ESI’s 119% Return Was More than 3.5 Times Our Peer Group

35. S&P Total Return – 2005 Only 2 Companies in the S&P 500 Exceeded ESI’s Total Return to Stockholders of 119% in 2005 Note: Returns reflect stock price increase plus dividend yield

36. 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