An adequate propranolol dose to reduce 25% the initial heart rate was searched in 19 children with portal hypertension. 13 were pre-hepatic and 6 hepatic hypertension, mean age: 6.96 +/- 3.48 years, range: 2-14 years. Treatment was started with 0.5 mg/kg/day increasing 0.25 mg/kg/day every third day, needing an average of 26 +/- 13 days (range: 6-54 days) to obtain the response. Daily dose ranged from 1 to 5.25 mg/kg/day (mean: 2.69 +/- 1.16). The highest daily dose was 175 mg, the lowest 23.4 mg (mean: 58.27 +/- 36.6 mg/day). Some parameters were evaluated before and after achieving the dose. There was a significant reduction of mean blood pressure (p < 0.01) and peripheral venous pressure (p < 0.05) in 68.4% of patients. A significant elevation (p < 0.001) of 24 hour urinary catecholamine levels occurred in 94.7%. Side effects were minimal. Propranolol could be considered a safe pharmacological option in these patients.