The aim of this study was to evaluate the antihypertensive efficiency and tolerance of diuretic indapamide. Thirtyone patients with mild and moderate hypertension underwent blood pressure measurement and 24-hour ambulatory blood pressure measurement before treatment and after four weeks of treatment with indapamide. Within 4 weeks of mono- or combined therapy with indapamide, systolic blood pressure fell from 154.0±13.2 to 135.8±11.6 mmHg and diastolic blood pressure fell from 94.6±9.2 to 84.1±9.1 mmHg (p<0,05). According to the data of 24-hour blood pressure monitoring mean systolic blood pressure and minimal systolic blood pressure had decreased significantly by the 28th day of the treatment: 140.9±15.5 vs 134.6±8.8 and 110.4±15.3 vs 100.2±7.9 mmHg, respectively. A similar tendency was observed in the changes of maximal systolic blood pressure, mean, minimal and maximal diastolic blood pressure and the MAP values. Treatment with indapamide did not statistically change the blood glucose, potassium, sodium, creatinine and uric acid levels. Indapamide tolerance was good; side effects were revealed in three patients. Thus, indapamide is a highly efficient and well tolerated drug in treatment of arterial hypertension.