To determine the frequency of renal dysfunction associated with the use of aminoglycosides with cyclosporine A (CyA) in children, the records of 26 consecutive children receiving CyA after liver transplantation were reviewed. Fourteen patients with normal baseline serum creatinine concentrations received an aminoglycoside postoperatively. These children received CyA and an aminoglycoside for 249 days (average, 17.8 days/patient). Forty of the 249 days included treatment with vancomycin or amphotericin B. Twelve children (86%) showed no evidence of renal dysfunction after aminoglycoside therapy. Two children developed renal dysfunction and eventually succumbed. In neither case could aminoglycoside nephrotoxicity be identified as the main cause of renal dysfunction. Multiple other factors, including ischemia and high CyA concentrations, probably contributed to renal deterioration. We conclude that aminoglycosides can be used safely in children receiving CyA following liver transplantation, provided serum CyA concentrations are followed closely and other risk factors for renal dysfunction are minimized.