OBJECTIVE: To assess costs related to hypertension in the elderly and in patients under 65 years of age with uncontrolled hypertension in Poland. METHODS: The time horizon of the analysis was 12 months and a retrospective approach was applied. Calculations were made from the societal perspective and third party payer perspective. Both direct medical costs and indirect costs were included. A detailed cost analysis was made for the 4392 patients with uncontrolled hypertension, comparing elderly patients with patients under 65. Resource utilisation data were derived from a scientific project conducted among GPs in the whole of Poland in the year 2000. Data concerning the efficiency of blood pressure control were gathered from the Polish epidemiological study. Unit costs were obtained from the Polish National Health Fund. RESULTS: Among the 8.4 million hypertensive patients in Poland 57% receive active treatment, 80% (3.8 million) of which do not reach the appropriate blood pressure target. The distribution of the direct medical costs in patients with uncontrolled hypertension was as follows: drugs 29%, laboratory, diagnostic tests 13%, hospitalisation 27% and physicians' consultations 31%. Taking the societal perspective, the direct medical costs were higher by 8% in the elderly uncontrolled patients and amounted to €249.30 but indirect costs were more than 12 times lower in the elderly as compared to €241.85 in patients under 65. The total costs in the elderly uncontrolled patients assessed from the third party payer perspective were higher by 14% and amounted to €201.74. CONCLUSION: The costs related to uncontrolled hypertension constitute a considerable economic burden. Uncontrolled hypertension might be the cause of increasing expenditure on health care in the near future. Wider use of more efficient antihypertensive drugs may help to avoid this phenomenon.