Sixty-six patients with chronic hypertension were cared for during a total of 72 pregnancies. Patients were treated at home primarily by ≥4 hours of bed rest daily in the left recumbent position. Only patients whose diastolic blood pressures remained >1IO mmHg were treated with hydralazine (Apresoline, Ciba). With this plan of treatment there were only 3 perinatal deaths for an uncorrected perinatal mortality of 4.1% (1.4% corrected). Twenty-nine percent of the patients had babies that were small for gestational age, 13.8% had positive oxytocin challenge tests, and 38.8% developed superimposed preeclampsia. When compared with the outcome of previous pregnancies, the program of bed rest lowered perinatal mortality from 16.8 to 8.8%. Thus, it is suggested that bed rest together with the avoidance of diuretics and the judicious use of hydralazine results in the most favorable fetal outcome.