Nocardia infections are uncommon in recipients of heart, lung, or heart-lung transplants, but such infections are well described. Frequent episodes of rejection, high-dose prednisolone treatment, renal impairment, and prolonged respiratory support have all been shown to increase the risk of Nocardia infection in this group. In this retrospective review of 540 recipients of heart, lung, or heart-lung transplants, 10 patients developed Nocardia infection (frequency, 1.85%). Infection occurred at a mean +/- standard deviation of 13+/-14.5 months after transplantation. All patients had pulmonary disease with no evidence of extrapulmonary disease. The Nocardia infection did not contribute directly to patient deaths. Coinfection with other pathogens was present in 6 patients, and 2 patients had sequential infections. Radiological findings varied. All isolates were susceptible to trimethoprim-sulfamethoxazole, amikacin, and imipenem. Treatment regimens varied. Two (30%) of 6 patients treated with trimethoprim-sulfamethoxazole developed adverse reactions, which necessitated a change in antibiotic therapy. The optimal treatment regimen, which comprises both the antimicrobial agent and the length of treatment, is unclear.