OBJECTIVES Make a comparison between Atorvastatin 20mg and Rosuvastatin 10mg in the treatment of hypercholesterolemia in the Mexican public institutions. METHODS We performed a cost-effectiveness analysis comparing Atorvastatin 20mg with Rosuvastatin 10mg. The effectiveness outputs were percentage of Low Density Lipoprotein Cholesterol (LDL-C) reduction and percentage of patients that achieve ATPIII goals after one-year treatment. Effectiveness variables were based on the results of the STELLAR study and costs were obtained from a local wholesaler (NADRO) prices list. We used the National Health and Nutrition Survey (ENSANUT) of 2006 to gather general prevalence information. Results are reported in U.S. dollars with and exchange rate of 15 MXN per dollar. RESULTS Annual treatment cost of Rosuvastatin 10mg was $558.04 and Atorvastatin 20mg was $1,169.24. We found an annual difference of $611.2 per patient. This means that if all the population with hypercholesterolemia reported by the ENSANUT 2006 were treated with Rosuvastatin instead of Atorvastatin a total of $10,613 million would be saved by the payer. The cost of one patient achieving the ATPIII goal with Rosuvastatin was $680.13 while with Atorvastatin the cost was $1,565.88. Cost of 1% reduction of LDL-C was $12.18 for Rosuvastatin and $27.45 for Atorvastatin. CONCLUSIONS Rosuvastatin 10mg is more effective in both measurements (achieving ATPIII goals and reducing LDL-C) and is less costly than Atorvastatin 20mg, therefore dominates over the compared treatment. The use of Rosuvastatin 10mg instead of Atorvastatin 20mg translates in huge saving to the public institutions in Mexico.