To investigate the prevalence, correlates, attitude and treatment seeking behavior of erectile dysfunction (ED) in type 2 diabetes mellitus (T2DM) patients in the primary care setting, a multi-center cross-sectional survey using a structured anonymous self-administered questionnaire was performed in 10 general outpatient clinics. Of the 603 subjects (91% response rate), the prevalence of ED men, as defined by the International Index of Erectile Function, was 79.1%. Most subjects had mild ED (28.9%), followed by mild-to-moderate ED (27.9%), then moderate ED (13.4%) and severe ED (9%). Nearly 55% of those with ED did not consider themselves as having ED. Less than 10% of them had ever sought medical treatment, although 76.1% of them wished to receive management from doctor(s) should they be diagnosed with ED. They considered the most important management from doctors to be clinical assessment (41.7%), followed by management of potential underlying cause (37.8%), referral to specialist (27.5%), education (23.9%), prescription of phosphodiesterase type 5 inhibitors (16.9%) and referral to counseling service (6.7%). The prevalence of ED was strongly associated with subjects who thought they had ED (odds ratio (OR) = 90.49 (20.00–409.48, P< 0.001)) and were from the older age group (OR = 1.043 (1.011–1.076, P = 0.008)). In conclusion, ED is highly prevalent among T2DM men. The majority of them wanted management from doctors should they have ED, but only a minority would actually voice out the request. Screening of ED among T2DM men using structural questionnaire allowed the diagnosis of more than half of the ED cases, which otherwise would have gone undiagnosed.