Erectile dysfunction in men with multiple sclerosis (MS) is a very common symptom that often leads to a reduced quality of life. It is related to neurological dysfunction, psychological factors, side effects of medication or generalized MS symptoms, such as fatigue or micturition problems, usually in combination. The question of sexual dysfunction should always be broached during routine follow-up, regardless of age and social status. The possibility that erection problems can be a side-effect of drugs commonly used in MS must also be remembered. There are several effective pharmacological treatments, such as phosphodiesterase inhibitors and prostaglandin E(1) (alprostadil). The contraindications and side effects should be familiar to the MS doctor. Dose titration in the initial stages is recommended to avoid priapism. In the future, combinations of impotence drugs may be tested.