In this study, twenty five swabs and twenty five biopsies were collected from twenty five patients suffering from chronic osteomyelitis (one biopsy and one swab from each patient) from Al-Yarmouk Teaching Hospital , Surgical Specialist Teaching Hospital and Baghdad Teaching Hospital in Baghdad during the period June 2010 to May 2011 Results showed that the most common affected gender with chronic osteomyelitis were males with 84% , and the highest incidence were recorded at the age group of 30-39 years distributed between (7) for males (28%) and (3) for females (12%) . Depending on cultural , microscopic examination and biochemical haracterization , results of both swab and biopsy specimens showed that 50% of the isolates were Staphylococcus aureus , 26% Enterobacter cloacae , 14% Pseudomonas aeruginosa , 6% Escherichia coli , and 4% Klebseilla sp. Results of the antimicrobial susceptibility test showed wide variation in response to different (11) antibiotic used . All isolates of S. aureus were totally resistance to methicillin , vancomycin , cephalothin and tetracycline followed by clindamycin, gentamicin and penicillin with percentage of resistance of 83% . On the other hand, all S. aureus isolates were completely susceptible to ciprofloxacin , chloramphenicol , novobiocin and rifampicin . A similar result was obtained, when three isolates of Enterobacter cloacae were resistant to ampicilllin, amoxicillin, cephalothin, tetracycline, vancomycin, rifampicin and penicillin , two of them resistant tochloramphenicol and trimethoprim and only one isolate resisted gentamicin . All were susceptible to nalidixic acid and ciprofloxacin
