Peripheral neuropathy commonly occurs in patients with chronic obstructive lung disease (COPD). The aim of our study was to investigate the possible effects of COPD on the peripheral nervous system. We enrolled 31 patients (16 women and 15 men), mean age 66.12, with COPD into the study. Arterial oxygen tension (PaO2)> or = 65 mmHg was considered as the cut-off value designating tissue hypoxia. According to this cut-off value, the subjects were divided into two groups: Group I (n=16), PaO2< 65 mmHg and Group II (n=15), PaO2> or = 65 mmHg. In all patients and controls, motor and sensory nerve conductions were studied with an electromyogram (EMG). We detected neuropathy in 93,5% of the study patients on EMG. In the Group I, severity of neuropathy was correlated with the degree of hypoxemia, but no correlation was observed in the Group II. In conclusion, the incidence of sensorial neuropathy was more than expected, the rate of axonal neuropathy was significantly higher in the group I than group II and the severity of neuropathy was correlated with the degree of hypoxemia in group I. From these data we suggest that electrophysiological studies may be useful in assessing the peripheral neuropathy in patients with COPD.