One hundred thirty-seven courses of furosemide therapy were given to 106 hospitalized pediatric patients with salt and water retention associated with cardiac or renal disease. The diuretic was effective and safe in the pediatric age group when administered acutely as a parenteral medication and over a long-term course by the oral route in the doses and at the time intervals used in this study. On the basis of each kilogram of body weight, the infants with edema as a result of cardiac failure and the children with edema secondary to renal disease responded equally well to furosemide therapy.