Background. Use of tacrolimus (FK506), a potent immunosuppressive agent, has been reported to have a 10-20% incidence of insulin-dependent diabetes mellitus (IDDM) in adults, but the incidence of IDDM in pediatric renal transplant recipients treated with this agent is unknown. In this article, we report our single-center experience with FK506-induced IDDM in children. Methods, Five consecutive living related donor pediatric renal transplants were reviewed retrospectively. Results, All five patients developed IDDM lasting longer than 6 months. Mean follow-up time was 18.6 months, Conclusions, Pediatric patients may be at high risk for developing FK506-induced IDDM.