en مقاله کامل Full Length/Original Article In this survey, 187 samples collected from 9 different sources of water in Tehran such as: water cool‌ers, neonates incubators, water bathes (37° C), little pools in parks or squares, cooling towers, hot or cold water taps, were examined for Legionnaires' disease agents. Inoculating water samples on selec‌tive and nonselective media resulted in isolation of several strains of gram negative bacteria. Among them, seven strains of Legionella pneumophilla which did not grow on any of the above media, were identified by indirect fluorescent antibody technique (IFA) and biochemical tests. Following confir‌mation by "Center National De Reference Des Legionelloses, Faculte of Medicine Alexis Carrel, Lyon", the Center identified Legionella pneumophila of serogroups of 1, 8 and 10. Out of 6 hospitals, 5 showed contaminated water having pneumonic Legionellosis agents. Legionnaires' disease, Legionella 83 87 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-439&slc_lang=en&sid=1 Mojtaba Moosavian مجتبی موسویان Yes Bahram Fathollahzadeh بهرام فتح الله زاده No Kazem Amoli کاظم آملی No Nasrin Moazzami نسرین معظمی No