Varivax has proven safe, immunogenic, and effective in the normal host and has been recommended for universal administration in the general population at age 12 months. It is not currently labeled for use in immunocompromised patients. However, recent studies in pediatric leukemia and pediatric renal transplant patients suggest that attenuated live vaccine can confer protection with minimal adverse events even in the presence of immunosuppression, providing encouragement for more careful studies of VZV immunization in renal transplant patients. This study aims to quantify the safety and immunogenicity of Varivax in the population of pediatric renal transplant patients least susceptible to VZV infection, i.e., those on minimal maintenance immunosuppression and at least 1 year out from transplant.