Blood pressure (BP) control is the easiest way to prevent complications, but in real practice and even in the majority of randomized trials it remains far from target. In diabetic patients the target BP is achieved less than in majority hypertensives and needs more efforts. The aim of this study was to compare diabetic and non-diabetic hypertensive patient characteristics and to evaluate the possibility of BP control depending on concomitant diabetes mellitus. 10 158 patients (12.7 % with newly diagnosed hypertension) with BP > 140/90 mmHg were included in 3 months multicentre (62 towns and 531 primary care physicians) open trial. All patients were divided into groups with concomitant diabetes mellitus (DM) type 2 (n=1208) and without DM (n=8950). Patients were treated by primary care physicians. Baseline patients with DM had higher systolic and diastolic BP, more percentages of complications (heart failure, nephropathy, myocardial infarction, stroke), concomitant coronary artery disease, risk factors (dyslipidemia, family cardiovascular history, age, obesity) and were less educated. Drug compliance was lower in DM patients baseline and at the end of study. Hypertensive patients with obesity (P<0.001) and low physical activity (P<0.005) had significantly higher percentage of DM type 2, than patients without obesity and higher physical activity. BP decreased significantly (P<0.001) in both groups. Yet, the level of BP in DM patients was higher than in non-DM patients. BP level < 140/90 mmHg was achieved in 54.7 % of DM patients and in 71.8 % without DM (P<0.001). BP level <130/80 mmHg was achieved only in 16.4 % DM patients. Predictors of poor BP control in DM hypertensives were older age, higher body mass index, complications (stroke, heart failure, retinopathy), coronary artery disease, family cardiovascular disease history, baseline high BP level, low drug compliance, low physical activity, low consumption of fresh vegetables or fruits. Higher BP was registered in patients with lower doses of antihypertensive drugs rarely using combination therapy.