A Legionella-like organism, strain 1407-AL-H, was isolated from a transbronchial lung biopsy specimen from a cardiac transplant recipient undergoing immunosuppressive therapy. The strain grew on buffered charcoal-yeast extract agar (BCYE) but not on BCYE in the absence of cysteine, and it showed gas-liquid chromatographic fatty acid profiles that were predominantly branch chained. Strain 1407-AL-H was antigenically distinct in slide agglutination tests from the 23 Legionella species and 39 serogroups previously described. DNA hybridization studies placed it in a new Legionella species, Legionella birminghamensis (ATCC 43702).