We report the first culture proven case of Legionella pneumonia in a HIV-positive patient in Italy. The laboratory diagnosis was obtained by isolation of Legionella pneumophila serogroup 1, serology, urinary antigen detection and PCR. Culture first allowed diagnosis of the infection, that probably would have been unrecognized. Since Legionellosis in HIV-positive patients with respiratory symptoms is rare and difficult to confirm, we strongly suggest that all available laboratory tests, and particularly culture, should be performed. A review of literature on culture proven cases is also provided.