Snoring and excessive daytime somnolence (EDS) are very common in middle-age adults. The goal of the investigation was to assess links between those symptoms and risk for cardiovascular diseases (CVD). The population studied included 1186 inhabitants of Warsaw (mean age 52 years), participants of the international multicentre study of cardiovascular disease MONICA II, who completed the sleep disordered breathing (SDB) questionnaire. Snoring was reported by 78% of males (48% habitual and 30% occasional) and 59% of females (27% habitual and 32% occasional). Every fourth (26.8%) subject declared observed apnoeas, in 9.2% apnoeas were observed every night. EDS was declared by 28.7% of studied sample. The results of the questionnaire were compared to the results of MONICA study. Snorers had significantly higher systolic and diastolic blood pressure (133.2 +/- 23/84.6 +/- 13 mm Hg) compared to non-snorers (126.4 +/- 22/80.4 +/- +/- 12 mm Hg) (p < 0.0001). The high total serum cholesterol (> or = 200 mg%) and triglycerides (> or = 200 mg%) concentration, and also obesity (BMI > or = 30 kg/m2) were more prevalent in snorers. Subjects reporting apnoeas more often had coronary artery disease (p < 0.001) or history of stroke (p = 0.002) compared to non-apnoeics. There was no relationship between EDS and risk of cardiovascular disorders, and also between diabetes and SDB. In conclusion, snoring was strongly associated with hyperlipidaemia, obesity or hypertension, well known risk factors for development of cardiovascular disorders. Reported apnoeas were related to risk of coronary artery disease.