We prospectively evaluated the feasibility of withdrawing steroids 6 to 12 months after heart transplantation in 26 consecutive infants and children (median age at transplantation 6 weeks; range 5 days to 10.1 years) initially treated with triple immunosuppression (cyclosporine, azathioprine, and corticosteroids). Ongoing surveillance for cellular rejection was performed by endomyocardial biopsy in all patients and was performed electively in all subjects within 2 weeks after administration of steroids was discontinued. Significant rejection was defined as grade 2. Twenty-three of 26 patients were 6-month survivors and steroids were withdrawn in 21, with the other two survivors followed up elsewhere with triple immunosuppression. Seventeen (81%) of 21 patients were ultimately treated without maintenance steroids for a mean duration of 17 months (range 1 to 34 months), including 6 of 17 patients who had at least one episode of rejection within the first 6 months of transplantation. Five (24%) of 21 patients had rejection 2 weeks (n = 3) and 6 months (n = 2) after steroids were withdrawn, with one patient successfully withdrawn from steroids after a second attempt. In this latter group one patient underwent retransplantation because of severe coronary arteriopathy by angiography 10 months after transplantation and another died suddenly 18 months after transplantation despite resumption of steroids.(ABSTRACT TRUNCATED AT 250 WORDS)