Renal transplantation is the treatment of choice for children with end-stage renal disease. Patient survival and allograft survival have improved with better immunosuppressant regimes to reduce acute allograft rejection but post-transplant infections have been exacerbated. An emerging problematic virus in the past decade is the polyoma virus BKV. The features of BKV including the clinical features in the general and immune compromised population are reviewed and correlated with pediatric studies in the post-transplant population. These features are placed in context with lessons learned about BKV in relevant adult studies.