Infectious episodes were analyzed in 14 heart-lung transplant recipients who survived more than one week after transplantation. These patients had higher rates of infection than heart transplant recipients at our institution (P<0.01) and greater than 90% of all infections were potentially life-threatening. A total of 67% of all infections involved the lung or thoracic cavity as a primary site, and most of the rest were disseminated viral or fungal infections. Pneumocystis carinii infections occurred in six patients and were more common in this group than in patients who received heart transplants in the same period (P<0.005). Two patients followed more than one year developed a syndrome of chronic sputum production and bronchial colonization with Pseudomonas aeruginosa, which required recurrent treatment with i. v. antibiotics for symptomatic relief. The high rate of pulmonary infections in these patients presents a challenge to clinical management, and suggests that intensive and invasive monitoring for pulmonary infection is desirable.