Immunodeficiency with thymoma (Good syndrome, GS) is a rare, adult-onset condition that is characterized by thymoma, hypogammaglobulinemia, and low numbers of peripheral B cells. CD4+ T lymphopenia and an inverted CD4:CD8+ T-cell ratio may be present. Here we report 5 patients with GS and infectious complications who were seen at 3 institutions between 1983 and 1999. Three patients had recurrent sinopulmonary infections, 3 had severe cytomegalovirus (CMV) disease, and 1 had Pneumocystis carinii pneumonia. Review of the literature identified 46 other reports of infections in GS patients. The infections reported in all 51 patients included recurrent sinopulmonary infection (19 cases with documented respiratory pathogens), generally with encapsulated bacteria, most often Haemophilus influenzae (11 cases); CMV disease (5 cases); bacteremia (7 cases); oral or esophageal candidiasis (6 cases); persistent mucocutaneous candidiasis (5 cases); chronic diarrhea (5 cases with documented stool pathogens); urinary tract infections (4 cases); P. carinii pneumonia (3 cases); tuberculosis (2 cases); Kaposi sarcoma (1 case); disseminated varicella (1 case); candidemia (1 case); wound infection with Clostridium perfringens (1 case); Mycoplasma arthritis (1 case); and other infections. Patients with GS present with a spectrum of sinopulmonary infections and pathogens similar to common variable immunodeficiency (CVID). Compared with patients with CVID, opportunistic infections, including severe CMV disease, P. carinii pneumonia, and mucocutaneous candidiasis, appear to be more common in patients with GS, and patients with GS may have a worse prognosis. GS should be ruled out in patients with thymoma or CVID who develop severe, especially opportunistic, infections. Treatment with intravenous immune globulin is recommended for all patients with GS.