Background Erectile dysfunction is an inability to initiate and have a persistent erection firm enough to have satisfying sexual intercourse. The prevalence of erectile dysfunction in diabetic men is considerably high, but it is often underdiagnosed and under-managed. Objective This study aimed to determine erectile dysfunction and associated factors among diabetic patients at, Hawassa, Southern, Ethiopia. Methods The institution-based cross-sectional study was conducted on 352 adult male diabetic patients randomly selected from Adare general and Hawassa comprehensive specialized hospitals using a simple random sampling technique. The number of patients to be selected from each hospital was proportionally assigned based on the total population of diabetes mellitus patients following chronic care during the study period. The descriptive statistics and multiple logistic regressions (bivariate and multivariate analysis) were carried out. Result The prevalence of erectile dysfunction was 72.2% (95%CI, 1.76–3.68). After adjusting all factors, old age, diabetes duration, drinking alcohol, and poor glycemic control had shown significant association with erectile dysfunction. Conclusion The occurrence of erectile dysfunction in this study community is very high. Drinking alcohol, poor glycemic control, age, and duration of diabetes were predictors of erectile dysfunction in this study area. Assessment and management of erectile dysfunction in the diabetic clinic should be part of routine medical care during follow-up visits with diabetic patients. Healthcare providers should emphasize screening and treating older patients and those who have had a diabetes diagnosis for a longer duration.