The article presents the results of a study of Legionella pneumophila morbidity in Lithuanian meat-processing factory workers, as well as the specific position of legionellosis in the fever diseases structure among the workers of the industry. The technique showed that Legionella pneumophila 1st serogroup seropositive reaction was traced among the healthy workers in 0.2% (antibody titer 1:64). Rather high percentage (7.1%) of persons with specific antibodies was found among those who had suffered the fever disease 6 month before the examination. Among 191 fever patients examined, in 35 (18.3%) cases antibodies against L. pneumophila were detected in diagnostic titers. In 26 workers legionellosis was diagnosed as a result of serologic testing, and Pontiac fever cases were predominant. 1 case was subsequently followed by pneumonia. A chronic nature of epidemic manifestations of legionellosis was established. The pathogenic antigen was detected in 4 of 32 water samples taken from the factory water pipes.