Pravachol and other statins have immune modulatory effects and have been shown to decrease the incidence of bronchiolitis obliterans (BrOb) in lung transplant recipients. It may also be useful in the treatment or prevention of hematopoietic stem cell transplant (HSCT) associated bronchiolitis obliterans. However, the safety of pravachol has not been shown in pediatric patients with BrOb after HSCT. We report on the safety and tolerability in 5 pediatric HSCT patients with established BrOb. All participants tolerated the drug without difficulty and there were no pravachol-associated adverse effects. Changes in creatine kinase (CK) and transaminases were minimal in 4 patients. One patient experienced increased CK and alanine aminotransferase, and a decrease in platelet count in the setting of severe systemic illness. No other patient had a clinically relevant change in white blood cell count, platelet count, or hemoglobin. Pravachol was well tolerated and safe in this group of patients, and merits further study in this patient population.