BK virus has become a serious issue in hematopoietic stem cell transplantation recipients, commonly manifesting as hemorrhagic cystitis, which can last from a matter of days to months and, if severe enough, may result in death. Patients with BK virus-associated hemorrhagic cystitis often experience poor quality of life, severe pain and discomfort, and prolonged hospitalizations. Despite numerous advances in stem cell transplantation methods, BK virus-associated hemorrhagic cystitis is difficult to control and treatment options are few. This article provides an overview of BK virus along with risk factors, current treatment modalities, and nursing considerations.