An 11-year-old boy developed Kaposi’s sarcoma and progressive T lymphocyte deficiency 5 years after cadaveric kidney transplantation for end-stage renal disease. He had received 17 individual red blood cell transfusions prior to and during transplantation in 1980. Human immunodeficiency virus (HIV) was cultured from blood in cerebrospinal fluid and HIV antibodies were detected with enzyme immunoassay and immunoblot techniques. The recipient of the donor’s other kidney was well and HIV antibody-negative. The patient was treated with etoposide with excellent although transient regression of tumor. Allograft function has remained stable despite minimal immunosuppressive therapy and the need for high-dose anticonvulsant therapy. This case represents the first pediatric patient with acquired immune deficiency syndrome (AIDS) and Kaposi’s sarcoma following kidney transplantation.