Between February 1980 and February 1992, 28 children (17 males and 11 females) were treated for endocarditis on congenital cardiac lesions, most commonly the mitral valve (32%). Their ages ranged between four months and 14 years (mean 8.2 years). The most common infecting organism (in 25% of patients) was Staphylococcus aureus. Patients were divided into two groups. In the first, made up of eight patients, cardiac surgery was undertaken within one week of the start of antibiotic therapy. The second group of 20 patients was further divided into a group of seven patients who underwent surgery during the initial, active stage of endocarditis because of failure of medical management and a group of 13 patients who initially received antibiotic therapy alone. In this last group, three infections with the same organism recurred within two months and surgical intervention was necessary in the active phase of the recurrence. Subsequently, surgery for “healed” endocarditis was undertaken in three more patients. Mortality in the 21 patients undergoing surgery was 19%—one of eight (12.5%) in those undergoing surgery within one week of starting treatment and two of 10 in the remaining patients. Overall, three patients (15%) died from those in whom surgery was not undertaken within one week of the start of treatment. There were also fewer pre- and postoperative complications as well as a lower mortality rate in those undergoing early surgery. We conclude that early surgical intervention, in our hands, is the most appropriate management for endocarditis in congenital cardiac lesions.