Pulmonary nocardiosis is an infrequent but insidious disease in transplant patients. It has occurred in our centre in 3 out of 233 heart-transplant recipients since 1988. Common clinical features were mild symptoms and a severe nodular lung involvement. Early diagnosis was based upon cultures of bronchoalveolar lavage or fine-needle aspirate specimens of the lung lesions. Susceptibility studies and tests of antibiotic synergism guided the therapy. Two patients were treated with a combination of piperacillin-tazobactam and ciprofloxacin, and one with imipenem and amikacin, for 3-4 wk followed by a 3-month course of trimethoprim-sulphamethoxazole. The nocardial disease was successfully treated in the 3 patients; however, one died of subsequent invasive pulmonary aspergillosis. In the absence of consensus on the length of therapy, this experience suggests that a synergistic combination of a beta-lactam/beta-lactamase inhibitor with ciprofloxacin or amikacin followed by a short course of trimethoprim-sulphamethoxazole may be effective in eradicating nocardial disease and may reduce the need for long-term treatment.