In the present report the authors discuss the diagnostic difficulties, therapeutic measures and the clinical course of Nocardia infection which occurred among renal transplant recipients at the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (UH-FRP), from 1968 to 1991. Among 500 individuals submitted to renal transplant, 9 patients developed Nocardiosis at varying times after transplant (two months to over two years). All the patients had pulmonary involvement and their most common symptoms were fever, cough and pleural pain. Dissemination of the process is common and three patients presented cutaneous abscesses, four CNS involvement and one had pericarditis due to Nocardia. The diagnostic is quite difficult since there is no specific clinical picture, concomitant infections are frequent and the microorganism presents slow growth in culture (ranging from four to forty days, in our experience). In this report, three cases were only diagnosed by necropsy. The treatment of choice is a combination of Sulfamethoxazole and Trimethoprim (SMX-TMP). In the present series, overall mortality was 77% (7 cases) and in five of the patients who died the diagnosis was late. All the patients who had CNS involvement died.