Abstract: The present invention provides a composition for improving sexual function comprising at least one compound as an active ingredient selected from the group consisting of arginine derivatives or pharmaceutically acceptable salts thereof. The composition of the present invention does not act as a substrate for arginase, but increases the generation of nitric oxide in endothelial cells along with enhancing the expression of nitric oxide synthase and induces the increase of the content of cGMP related to an erection depending on the concentration, thus remarkably exhibiting the effects of improving sexual function.