Chronic osteomyelitis is a persistent disease difficult to treat or eradicate completely. The prognosis depends heavily on proper identification and treatment of the bone-infecting organism. Change in the bacterial flora and indiscriminate use of antimicrobial agents has led to the emergence of multidrug resistant strains. One hundred chronic osteomyelitis cases attending Orthopaedic OPD and those admitted in Orthopaedic wards of K R hospital, Mysore medical college, Mysore were studied. Under proper aseptic conditions suitable specimens were collected, processed and isolates were identified   using standard laboratory techniques. There were 74 were males and 26 females. Majority of the patients were in the age group of 21-50 years (66%). Femur (49%) was commonly affected.  Monomicrobial flora was 63% and polymicrobial flora 19%. A total of 110 organisms were isolated, 101 (91.82%) were aerobes and 9 (8.18%) anaerobes. The most commonly isolated aerobes were Staphylococcus aureus (41.82%) and Pseudomonas Spp. (21.82%) and anaerobes were Peptostreptococcus Spp.(4.54%)and Bacteroides spp.(3.64%)  Trauma was the most common predisposing factor. In the present study S. aureus was the most common cause of chronic osteomyelitis followed by Pseudomonas Spp. Trauma was the most common predisposing factor.