Objective. A case control study to find out if Cuba's epidemic neuropathy was a result of one of the following causes: (1) an infectious process, (2) exposure to one or more toxical agents, (3) low intake of one or more nutrients, or (4) more than one of such causes and their interactions. Material and methods. A total of 311 cases of epidemic neuropathy with optic and peripheral symptoms and 377 controls were studied. A questionnaire with 55 items was employed to document exposure to factors determined by the etiologic hypothesis. Data analysis was done separately for the optical and peripheral types of the disease. Results. No association was found between illness and any deficiency of basic sanitation for both types of neuropathy. Acute stress, irregularities in food intake, body weight loss in the last 12 months and other indicators of nutritional deficiencies were associated to both clinical manifestations, although they were also high in the controls. Low frequency of illness was found for people living with diseased persons. Females had a significant high risk of illnes in the peripheral manifestations whereas smoking was the only toxical risk factor in optical neuropathy. Nutritional deficiencies together with unidentified personal factors were the main associations for illness outcome; smoking increased significantly the risk of optical neuropathy. Conclusions. 1. The infection etiology was unsupported in the study. 2. Smoking appeared as a factor for the optical neuropathy. 3. Stress induced by vital events were significantly associated with the disease. 4. Both types of the neuropathy were associated to body weight loss and other indicators of nutritional deficit.