A total of 4191 patients 55 years and older were screened for clinical features and risk factors of polyneuropathy by 27 general practitioners (GPs) in two areas of Italy (Varese and San Giovanni Rotondo). Polyneuropathy was diagnosed in the presence of two or more symptoms associated with bilateral impairment of at least two of the following: strength, sensation, tendon reflexes. A risk factor for polyneuropathy (associated disease or neurotoxic agent) was recorded based on its presence in the GP's records, the presence of specific treatments, or an affirmative answer to the interviewer's question. The prevalence of polyneuropathy among patients with no recognized exposure to diseases or neurotoxic agents was 1.6% (Varese 1.6%; San Giovanni Rotondo 1.8%). The corresponding values were 11.8% (Varese 11.8%; San Giovanni Rotondo 11.9%) for patients with one risk factor, and 17.3% (Varese 19.2%; San Giovanni Rotondo 13.0%) for patients with two risk factors. Combining the two populations, the prevalence of polyneuropathy was highest in diabetics (18.3%), followed by patients with a diagnosis of alcoholism (12.5%), non-alcoholic liver disease (10.9%), and tumor (7.1%). Diabetes was the commonest independent risk factor for polyneuropathy (odds ratio 11.3), followed by alcoholism (7.4), non-alcoholic liver disease (4.9), and tumor (2.6).