BKV was first postulated to be a potential pathogen in 1971 when it was isolated in the urine of a renal transplant recipient. The pathology of BKV is generally confined to the urinary tract. In renal transplant recipients, BKV has been associated with hemorrhagic cystitis, urethral stenosis, and interstitial nephritis. Reports of BKV infection in lung transplant recipients are limited to a few case reports in adult patients. A recent report revealed that up to 32% of adult lung transplant recipients may shed BKV in their urine without symptoms or renal dysfunction. To our knowledge, there are no published reports of pediatric lung transplant recipients with BKV-associated hematuria. We hereby report a case of BKV-induced hemorrhagic cystitis in a pediatric lung transplant recipient.