Studies have established correlation between consumption of fermented leguminous food products and lower incidences of chronic diseases. Hence, this study investigated the effect of some fermented legumes (soybean, locust bean, and bambara groundnut) on key enzymes implicated in erectile dysfunction (ED). The aqueous extracts of the fermented legumes were prepared (1:10 wt/vol) and their effects on arginase, phosphodiesterase-5 (PDE-5), acetylcholinesterase (AChE), and ecto-5' nucleotidase activities were determined in vitro. The results revealed that all the extracts inhibited arginase, PDE-5, and AChE activities in a concentration-dependent manner in vitro. However, soybean extract had the highest arginase (IC50=5.95 mu g/mL) and AChE (IC50=4.86 mu g/mL) inhibitory effect, whereas locust bean extract had the highest PDE-5 inhibitory effect (IC50=4.91 mu g/mL). In addition, all extracts exhibited stimulatory effect on ecto-5' nucleotidase activity. The observed effects of the extracts on these enzymes suggest their possible involvement in the management of ED. Practical applicationsData generated in this study reveal the effectiveness of some fermented legume seeds (bambara groundnut, locust bean, and soybean) in modulating the activities of some enzymes relevant to erectile dysfunction. In addition, these fermented legume seeds could serve as functional food in the management of erectile dysfunction.