The etiology of 209 cases of peripheral neuropathies was studied taking into account the most affected age ranges, as well as the sex and occupation of the patients. The age ranges of our patients for the polyneuropathies consequent to alcoholism, for diabetic polyneuropathy, for Guillain-Barré syndrome and for hereditary sensorimotor neuropathies were 20 to 50 years, 10 to 70 years and 0 to 30 years. The age range of patients with leprosy and nerve injury was 20 to 50 years, and more frequently up to 30 years. Alcoholic and diabetic polyneuropathies predominantly affected males, whereas injury to the median polyneuropathies affected laborers. Inactivity was reported by 1/3 of the patients with diabetic polyneuropathies, by 25% of the patients with polyneuropathies consequent to alcoholism and by 24% of the patients with undefined polyneuropathies.