The association between different antihypertensive drugs and erectile dysfunction (ED) was examined in a cohort of type II diabetes patients identified in the UK General Practice Research Database (GPRD). The GPRD contains details of diagnoses, prescribing, investigations, risk factors, outcomes, and hospital referrals, together with basic demographic information for approximately six million patients from more than 450 representative general practices throughout the UK. A total of 634 cases and 2526 controls were included for analysis. Unconditional logistic regression analysis was performed to assess the risk of ED after adjusting for age at diabetes diagnosis date, cigarette smoking, depression, glycemic control, use of HMG-CoA reductase inhibitors, use of histamine receptor antagonists, use of digitalis medicines, and use of nitrates. Increased risk of ED was observed among patients taking the following antihypertensives: ACE inhibitors (OR ¼ 1.47, 95% CI ¼ 1.21, 1.80) and alpha blockers (OR ¼ 1.54, 95% CI ¼ 1.11, 2.12). However, we identified a nearly 30% reduction in risk among patients on diuretics (OR ¼ 0.73, 95% CI ¼ 0.54, 0.99). No statistically significant increase in risk was observed among users of beta blockers and calcium channel blockers (OR ¼ 1.05, 95% CI ¼ 0.85, 1.31) and (OR ¼ 1.14, 95% CI ¼ 0.91, 1.43), respectively. The results of this study confirm the strong and recognized effect of comorbidities in a diabetic population, but also require additional experimental and observational studies to further understand the potential benefit of diuretics and other ED treatments such as PDE5 inhibitors.