BACKGROUND Nocardiosis has emerged as an important bacterial disease among renal transplant recipients, leading to considerable morbidity and mortality. Apart from the increasing problem of resistance in pathogenic nocardiae, the spectrum of species causing disease has enlarged in recent years. There are no published reports on nocardiosis from Middle-East countries. METHODS A retrospective review of case records of 513 renal transplant recipients between January 1989 and January 1995 was done in the transplant unit of our hospital. Information was collected on clinical details, type of donor, immunosuppressive therapy, prophylaxis, and outcome. Isolation of Nocardia species from appropriate clinical specimens was the sole criterion for diagnosis. RESULTS Nocardiosis was diagnosed in six recipients with a disease incidence of 1.2%. Four patients had received unrelated kidneys. Co-morbid conditions were diabetes mellitus (3), viral hepatitis (2) and neutropenia (1). Clinical manifestations included deep-seated skin abscesses and pulmonary disease in three each. Cerebral abscess and meningitis were found in two patients with pulmonary disease. Pathogens were Nocardia asteroides in four and N. otiti discaviarum and N. farcinica in one each. In contrast to in vitro susceptibility results, clinical response was different in that five patients who received trimethoprim-sulphamethoxazole (TMP-SMX) alone (2) or in combination with cefuroxime (3) responded well. CONCLUSIONS The study stresses a high index of suspicion for nocardiosis in susceptible hosts who present with cutaneous abscess, pulmonary infiltrative lesions, and cerebral manifestations. TMP-SMX in combination with cefuroxime seems to be a highly effective therapy. It does not appear mandatory to reduce or discontinue immunosuppressive therapy during treatment of nocardiosis.