Metformin reduces total cholesterol level, low density lipoprotein cholesterol (LDL-C) level, blood glucose level and increases high density lipoprotein cholesterol (HDL-C) level associated with cardiovascular disease. We evaluated effect of metformin on lipid profile in Korean patients with type 2 diabetes aged 64 yeras or older. We retrospectively examined 307 outpatients treated with metformin in a hospital setting with a follow-up period of 4.7 years. Metformin was not associated with the improvement in total cholesterol level (adjusted mean difference; 30.6 mg/dl, 95% CI: 24.9 to 36.4) and HDL-C level (adjusted mean difference; 2.6 mg/dl, 95% CI: 0.09 to 4.64) but may be associated with improvement in triglyceride level (adjusted mean difference; 41.5 mg/dl, 95% CI: 24.7 to 58.3). In comparison to the placebo groups (Kooy et al., 2009), there was a 1.5-fold decrease in triglyceride level and a 2-fold decrease in HDL-C level in our study. The frequency of Scr level that increased above the defined level [Scr ${geq}$ 1.5 mg/dl for male, ${geq}$ 1.4 mg/dl for female] was 6.7% [mean difference of elevated Scr: -0.9 mg/dl, 95% CI: -0.41 to -1.44, p < 0.002]. To confirm the efficacy of metformin use on triglyceride level and HDL-C level associated with the risk of cardiovascular disease in patient with diabetes, further placebo-controlled investigations are required.