Anti-tumor necrosis factor-alpha therapy, infliximab, has become an established effective therapy for Crohn's disease and rheumatoid arthritis. However, infliximab has been associated with various opportunistic pathogens such as tuberculosis, histoplasmosis, listeriosis, aspergillosis, and Pneumocystis jiroveci (carinii) pneumonia. We reviewed the FDA Adverse Event Reporting System for cases of Pneumocystis associated with infliximab use from January 1998 through December 2003. The database revealed 84 cases of PCP following infliximab therapy. Concomitant immunosuppressive medications included methotrexate, prednisone, azathioprine, 6-mercaptopurine, and cyclosporine. Mean time between infliximab infusion and onset of symptoms of pneumonia, when reported, was 21 days (+/-18 days; n=40). Twenty-three of the 84 (27%) patients died. The use of infliximab is associated with PCP infection. Further, the mortality rate for Pneumocystis following the use of infliximab is significant. The potential for severe disease, mortality, and often subtle presentation of these infections warrant close follow-up and careful monitoring after therapy.