For identification of gram-negative bacteria leading to chronic otitis media and for determination of their susceptibility to antibiotics, ear drainage materials sent to Microbiology Department, Yakutiye Research Hospital, Atatürk University in 1998 were evaluated. Gram negative bacilli were isolated from 319 specimens of these specimens 134 were Pseudomonas aeruginosa, 63 Proteus spp., 55 E.coli, 45 Enterobacter spp., 9 Citrobacter freundii, 5 Citrobacter diversus, 3 Providencia, 3 Serratia marcences and 2 Klebisella pneumoniae. The most effective antibiotics were imipenem (93%) for P.aeruginosa, and ciprofloxacin for Proteus spp. (96%), E.coli (98%) and Enterobacter (97%).