In 203 HIV infected patients in various clinical stages neurological examination, paired stimulation (LPSS), nerve conduction velocity (NCVS) and amplitude (AMPS) of the sural nerve, distal latency (DLP), nerve conduction velocity (NCVP), amplitude (AMPP) and F waves of the peroneal nerve were recorded. Neurological examination revealed symptoms and clinical signs of polyneuropathy in 67 (33%) (WR 1-6) of the patients. LPSS after paired stimulation was abnormal in 25.5%, NCVS in 14.2%, AMPS in 9.8%, NCVP in 11.8%, DLP in 11.2%, AMPP in 5.9% and FWP in 14.6%. Our findings indicate a high incidence of peripheral nerve system involvement during HIV infection. In 11.5% of all patients only LPSS proved polyneuropathy. Neurophysiological results from HIV infected patients with symptoms and clinical signs of polyneuropathy were statistically significantly different from HIV infected patients without symptoms and clinical signs of polyneuropathy. The delay of LPSS represents the most sensitive neurophysiological indicator of polyneuropathy during HIV infection and announces the onset of peripheral nerve disease even in early stages of infection, according to Walter Reed staging classification 1 and 2 (approx. 20%).