Toxoplasma pneumonia is being recognized with increased frequency, especially in patients with AIDS. We reviewed the English-, French-, and Spanish-language literature from January 1966 through February 1991 to identify cases of postnatally acquired pneumonia associated with Toxoplasma gondii. We identified two distinct clinical syndromes, one in immunocompetent patients and one in patients with defects in cell-mediated immunity. Shortness of breath and cough were the most common symptoms and fever and rales the most common signs in both groups of patients. Lymphadenopathy and hepatosplenomegaly were reported more frequently for immunocompetent patients. Chest roentgenographs usually revealed bilateral interstitial infiltrates, but a variety of other roentgenographic findings were reported. Serological findings were suggestive of active toxoplasmosis in immunocompetent but not in immunosuppressed patients. In early reports, identification of T. gondii as the etiologic agent of pneumonia was based on serology or autopsy findings. In more recent reports, open lung biopsy and especially bronchoalveolar lavage were used for diagnosis. Mortality among patients with toxoplasma pneumonia was 55%. However, in cases of T. gondii pneumonia diagnosed during life, mortality was 0 for immunocompetent patients and 40% for immunosuppressed patients. In immunosuppressed patients, improvement was associated with specific antitoxoplasma drug therapy. Unfortunately, relapses were common. We also reviewed data on series of patients with disseminated toxoplasmosis manifested predominantly in extrapulmonary sites and found that 33% of these patients had evidence of subclinical pulmonary involvement even though pneumonia had not been diagnosed clinically.