Cat scratch disease (CSD) can lead to unexplained fever, generalized lymphadenopathy and organomegaly in immunocompetent individuals. CSD has rarely been reported in immunocompromised transplant recipients, where its clinical features would mimic the more common post-transplant lymphoproliferative disease (PTLD). We report three cases of CSD seen recently in children who had received prior kidney transplants. The three children were between 7 and 9 yr old, and had received kidney transplants 2-4 yr prior, with stable renal function. In each case, there was unexplained fever with either lymphadenopathy or organomegaly. The diagnosis of CSD was suggested by a history of new cats being introduced into each household and confirmed in all cases by the serological presence of a significant titer (> 1 : 64) of IgM antibodies to Bartonella henselae. Tests for other bacterial infections, cytomegalovirus and Epstein-Barr virus infections were negative. All the patients showed a clinical improvement with anti-microbial therapy. In patients A and B, the CSD was associated with an acute rejection episode shortly after diagnosis. The rejection episodes were reversed by intravenous steroid pulse therapy. Only four cases of CSD have been previously reported following solid organ transplantation. Acute rejection following CSD has not been previously reported. CSD should be included in the differential diagnosis of fever in the post-transplant setting, especially where PTLD is suspected.