Objective: To compare serum Prolactin levels in patients with erectile dysfunction (ED) with and without type-2 Diabetes Mellitus Materials and methods: This cross-sectional descriptive study was conducted over 100 Diabetics and 100 non-Diabetics patients with ED and their serum Prolactin levels were measured in all and compared in 2 groups. A convenience sampling technique was used to select patients from two Hospitals, i.e, Khyber teaching hospital Peshawar and Government Naseerullah Babar hospital, Peshawar. Independent sample t-test was performed for comparison between two groups. Results: Serum Prolactin levels were high in diabetic patients with ED. Majority of patients were 40-49 years old. Duration of ED was higher in Diabetics patients as compared to Non-Diabetics. Conclusion: ED is common in age group 40-49 years and in diabetics than in non-diabetics and is associated with high levels of serum Prolactin levels respectively. The duration of ED was also found to be more in diabetics than non-diabetics. [ABSTRACT FROM AUTHOR]