We performed this population-based study to investigate the effects of atorvastatin and rosuvastatin on renal function in patients with type 2 diabetes. From the Taiwan National Health Insurance Pay-for-Performance program for diabetes mellitus database, 2006 to 2009, type 2 diabetic patients aged 40 to 100 years with the first prescription of atorvastatin or rosuvastatin were identified. All the data were linked to the National Health Insurance claims database, 2000 to 2010, to construct longitudinal health care data. The Modification of Diet in Renal Disease equation was used to calculate the estimated glomerular filtration rate (eGFR), and the eGFRs between baseline and the end of follow-up (maximum 2 years) were compared. Totally, 3,601 new users of atorvastatin and 1,968 new users of rosuvastatin were included. The median follow-up was 238 days in atorvastatin users and 210 days in rosuvastatin users. The eGFR at baseline was 72.3 ± 25.9 ml/min/1.73 m² in atorvastatin users and 73.7 ± 27.3 ml/min/1.73 m² in rosuvastatin users. In both statin groups, we found no significant change in eGFR (+0.1 ml/min/1.73 m², 95% confidence interval −0.4 to 0.7, p = 0.62 in atorvastatin users; −0.1 ml/min/1.73 m², 95% confidence interval −0.8 to 0.6, p = 0.77 in rosuvastatin users). In conclusion, neither treatment with atorvastatin nor rosuvastatin was associated with a significant change of renal function in type 2 diabetic patients.