Viral infection or reactivation in immunocompromised patients is a well-studied phenomenon in the field of pediatric bone marrow transplant. Severe viral disease can lead to encephalitis, liver failure, and engraftment failure, in addition to toxicity from antiviral therapies. Still, there is debate as to which viral diseases contribute most to serious clinical complications, and thus, which viruses require prophylactic treatment. In this study, we utilize a historical database of all pediatric hematopoietic stem cell transplant patients cared for in the Division of Pediatric Hematology/Oncology at UCLA and report a retrospective assessment of these patients focusing on viral diseases and clinical outcomes. Along with demographic data, patients were characterized by potential risk factors for viral disease, such as primary disease, transplant graft, match status, and pre-engraftment viral serology. We report 172 transplants in the service in the period from January 2008 through September 2017. Of the 40 patients who died, we have identified 17 cases in which infections by CMV, HSV, adenovirus and HHV-6 had a relevant role in their demise. The incidence of seven common viral diseases was also documented (CMV (25.6%), EBV (20.9%), HSV (1.2%), adenovirus (9.3%), BK (11.6%), HHV-6 (16.3%)). Infection or reactivation of these viruses contribute to substantial morbidity and mortality in the pediatric bone marrow transplant patient population, and thus, further studies will investigate the susceptibility to reactivation as well as potential prophylactic methods that can improve patient care.