Aim: To examine prevalence and control of the blood pressure (BP) in the general population and in a subgroup of individuals with diabetes mellitus (DM) receiving primary care in the Czech Republic. Methods: A total of 150 primary care physicians examined and recorded the data of 15 consecutive patients (aged ≧45 years) each, irrespective of the visit purpose. A total of 2,211 patients were included; 403 of them had DM. Results: Of the patients screened, 78.4% had hypertension (BP ≧140 and/or ≧90 mm Hg) or were on antihypertensive therapy. In the DM patients, the prevalence of hypertension was higher than 91.3%. Hypertension control (target <130/<80 mm Hg) was only obtained in 18.4% of the general population and in 4.0% of the patients with hypertension and DM. Systolic BP control deteriorated significantly with age, with ≧140 mm Hg present in 75.9–93.1% in the age groups 65–74 years and ≧74 years as compared with 57.1–76.8% in the younger age groups (p = 0.02–0.008). A diastolic BP reduction to <80 mm Hg was achieved in only 8.9–17.2% of the patients. Conclusions: Our survey shows that the target BP is achieved in <5% of the hypertensive patients with DM. The poor hypertension control in patients with DM is primarily due to inadequate systolic BP control, deteriorating significantly with age. The results are alarming and emphasize the need for a more aggressive treatment strategy in patients with DM.