Introduction: Diabetic men with erectile dysfunction have not been widely studied. They have low testosterone levels, causing low sex drive and erectile dysfunction. Aim: To assess the erectile dysfunction and sex drive in relation to testosterone serum levels in type 2 Diabetes Mellitus (DM) patients. Materials and Methods: A total of 64 patients with type 2 DM were enrolled in this cross-sectional study, according to the treatment types they were divided into three groups, group (A): 34 patients treated with metformin, group (B): 30 patients treated with sulfonylurea and group (C): 27 healthy normal non-diabetic men are taken as control. Total testosterone (TT), Free Testosterone (FT), Free Androgenic Index (FAI), Sex Hormone Binding Globulin (SHBG), lipid profile and anthropometric parameters in metformin and sulfonylurea treated patients were compared to normal healthy men along with Sexual Health Inventory for Men (SHIM). Results: Total testosterone serum levels were high in sulfonylurea treated patients as compared to metformin treated patients' p < 0.0001. Similarly, SHBG levels were significantly higher in sulfonylurea treated patients compared to metformin treated patients p < 0.0001. FT was also significantly higher in sulfonylurea treated patients compared to metformin treated patients p = 0.014 and significantly low compared to the control p = 0.0002. FAI was also significantly higher in sulfonylurea treated patients compared to metformin treated patients p < 0.0001. On other hand Bioavailable testosterone (BT) was low in metformin treated patients (2.75 +/- 1.12 nmol/L) compared to the control p< 0.0001. SHIM was low in metformin treated patients 10.61 +/- 3.22 which significantly differed from control and sulfonylurea treated patients p< 0.0001, intergroup differences was significant p=0.001. Conclusion: Metformin leads to significant reduction in testosterone levels, sex drive and induction of low testosterone-induced erectile dysfunction, whereas; sulfonylurea leads to significant elevation in testosterone levels, sex drive and erectile function.