Stavudine (2',3'-didehydro-3'deoxythymidine) is a pyrimidine analogue that may be of great value in combination antiretroviral therapy (ART) for treating patients infected with human immunodeficiency virus type 1 (HIV-1). We assessed potential neurotoxic side effects by comparing peripheral nerve function in patients receiving ART including stavudine (n = 107) with that of patients receiving ART with zidovudine (n = 103). A cross-sectional analysis of electroneurographic data revealed no significant differences. In a follow-up examination of 31 patients newly started on ART with stavudine we observed no significant effects of the drug on electrophysiological measures. At a daily dose of 1.0 mg/kg the incidence of peripheral nervous system disease in our patients was about 10%. Repeated follow-up analysis of 13 patients on stavudine showed a significant reduction in sural nerve amplitude. Quantitative sensory testing in 13 patients revealed no systematic effect of stavudine on small nerve fibers. Peripheral nerve function in HIV-1 seropositive patients on ART with stavudine did not differ significantly from that in patients on ART with zidovudine. Therefore stavudine at a daily dose of 1.0 mg/kg is an alternative for patients who do not tolerate, or who have become resistant to zidovudine and can be recommended as a first-line drug in combination ART.