Objective: To compare the risk of cancer between Atorvastatin and Simvastatin users. Methods: Retrospective cohort study was conducted in Louisiana Medicaid program from January 1, 1998 through June 30, 2005. Inclusion criteria were recipients continuously eligible with no more than two months gap, a paid claim for statin, and at least 40 years of age. Patients with diagnosis or drug claim for cancer in the washout period were excluded. Washout period was defined as a period between index date minus 12 months and index date plus 18 months. Statin (Atorvastatin or Simvastatin) users were patients with 300 or more days of supply of statin within 18 month period from the index date. Patients were then followed for at least six months or until end of study period. A propensity score-based matching method was used to match both the groups (1:1 match). Users of Atorvastatin were compared with the users of Simvastatin as to their risk of cancer. Results: Each group had 1050 recipients after matching for comparison. Compared with Atorvastatin users, Simvastatin users experienced similar cancer risk (OR 1.20, 95% C.I. = 0.78-1.82). Conclusion: The data from present study provides evidence that there is no significant difference in risk of cancer between Atorvastatin and Simvastatin users.