Type 2 diabetes mellitus (DM) is a growing global epidemic, especially among aboriginal Taiwanese. This study aimed to identify the relationship between erectile dysfunction (ED), markers of endothelial function, serum testosterone level and type 2 DM in aboriginal Taiwanese. Data were obtained from a baseline survey of 240 aboriginal adults. Their demographic data, presence of type 2 DM, markers of endothelial function, serum testosterone and ED status were assessed. The mean age of the samples was 51.62 ± 7.76 years. The International Index of Erectile Function-5 total score had a mean of 21.99 ± 2.34 and a median of 23; 134 participants had ED (55.8%). The results showed an increased risk of ED for participants with type 2 DM and lower serum testosterone level. Among the predictors of ED, type 2 DM, lower serum free testosterone and high-sensitivity C-reactive protein were significantly independent factors. Interleukin-6 had a negative relationship with ED. The study results suggest there is a strong association between type 2 DM and erectile function among aboriginal Taiwanese that is similar to the general population. This study also supports the idea that type 2 DM, markers of endothelial function and serum testosterone may provide warning signs of ED and, at the same time, an opportunity for early intervention for aboriginal adult male.