The prevalence of type 2 diabetes mellitus (DM 2) has increased dramatically in the last decade. Data relating to the number of undetected cases of diabetes are underestimated. The aim of the study was to evaluate the prevalence of DM 2, obesity, hypertension, and lipid disturbances in a representative group of urban and rural population in the Lublin region (Eastern Poland). The study was performed in 1998-2001. A two-layer draw was applied: two groups of 3000 people were drawn from the population of Lublin town and from the rural areas each comprising 100,000 inhabitants. In all subjects physical examination was performed and body weight, height, and blood pressure measurements were obtained. Blood samples were taken from the basilic vein to estimate: blood glucose, lipids and insulin concentration. Venous blood glucose concentration was measured using a Glucotrend glucometer. Oral glucose tolerance test (OGTT) after a 75 g-glucose load was performed in subjects without previously diagnosed diabetes mellitus and when the fasting blood glucose was < 8.0 mmol/l (144 mg/l). The LDL-cholesterol level was calculated according to Friedewald formula. DM 2 was identified according to the WHO criteria from 1985. Obesity and hypertension were diagnosed according to the new WHO criteria (Body Mass Index > or = 30 kg/m2, blood pressure > or = 140/90 mm Hg). 3782 subjects: 1809 in the rural area and 1973 in Lublin town were examined. The response rate among rural and urban population was 60.3% and 65.8% respectively. The prevalence of DM 2 was assessed in 17.6% of rural and in 14.1% of urban population. 75% of diabetics in the rural areas and 56% in the town were the newly diagnosed cases. We found impaired glucose tolerance in 30.3% of rural and in 21.6% of urban population, BMI > or = 30 kg/m2 in 30.8% and 30.1%, hypertension in 69.4% (29.2% newly diagnosed) and 68.6% (27.7% newly diagnosed), hypercholesterolaemia (total cholesterol > or = 5.2 mmol/l (200 mg/dl)) in 66.4% and 60%, hyper-LDL-cholesterolaemia (> or = 3.5 mmol/l (135 mg/dl)) in 57.3% and 52.6%, hypo-HDL--cholesterolaemia in 21.7% and 31.4%, hypertriglyceridemia (> or = 2.3 mmol/l (200 mg/dl)) in 15.1% and 22% respectively. This finding indicates the urgent need for introducing a national program for early diagnosis and prevention of DM 2 and concomitant metabolic disturbances.