One-year open Multicentric Isradipine Study (MIS) performed in 7 centres in Czechoslovakia included 144 patients with mild and moderate hypertension. Isradipine was given at a dose of 2.5 mg daily. If normalization of diastolic blood pressure (BP) had not been reached, the dosage was increased to 5 mg. Monotherapy with isradipine normalized diastolic BP in 44% of patients. Isradipine (5 mg daily) was combined with bopindolol in patients in whom isradipine alone failed to normalize diastolic BP. These had higher mean systolic and diastolic BP, body weight, erythrocyte and platelet counts at the beginning of the study. The combination of isradipine with bopindolol normalized diastolic BP in 87% of the group at the end of 48 weeks' treatment. Tolerance was excellent in 82% of patients. Treatment was discontinued in 8% patients, undesirable effects being the reason in 2%, ineffective therapy in 2% and poor adherence to therapy in 4%. Isradipine in monotherapy or in combination with bopindolol did not exert an adverse effect on the metabolic risk factors of ischaemic heart disease (cholesterol, glycaemia).