In a case-control study, we investigated the connection of sleep apnea (OSA) with occupations and occupational exposure to neurotoxic substances such as varnish, pesticides, lead, arsenic and mercury. 443 OSA cases were compared with 397 population controls (1st control group) and with 106 patients with OSA having been excluded during the investigation period (2nd control croup). Data were gathered by means of a self-administered questionnaire. Adjusted odds ratios were calculated for age, region, body-mass index (BMI), cigarette smoking and alcohol consumption using logistic regression analysis. There were discrete indications of a possible relationship between OSA and exposure to mercury and to pesticides. At the time of diagnosis, OSA patients were significantly more often occupied in service occupations; this might be explained by epidemiological aspects (reporting and treatment behaviour, insurance in case of illness). In summary, these results do not support any indications of an etiological significance of occupational factors.