Sexual dysfunction in multiple sclerosis (MS) has only recently become recognized as an early and distressing manifestation of the disease in both sexes. Sexual problems appear to be a combination of direct neurological consequences, and of individual and partner reactions. This article reviews current knowledge about sexual dysfunction in MS. The major effects on sexual response (both organic and psychogenic) are discussed, as well as associated physical problems and implications regarding fertility, pregnancy and birth control. Guidelines for intervention by neuroscience nurses who work with MS individuals and their partners are addressed.