Introduction: In recent times, there has been change in bacteriological profile of chronic osteomyelitis cases as well as susceptibility of antibiotics. Objectives: 1. To study Demographic characteristics of Chronic Osteomyelitis cases, 2. To isolate causative Aerobic bacteria (other than Mycobacteria) 3. To analyze Antimicrobial Susceptibility Pattern of isolated aerobic bacteria. Methodology: A cross sectional hospital-based study of 1 year duration was conducted at Department of Microbiology, S. P. Medical College, Bikaner, Rajasthan. After obtaining informed verbal consent, 110 chronic osteomyelitis cases were recruited to study following nonprobability consecutive sampling. Their pus samples were taken and studied for staining, presence of enzymes, biochemical reactions, fermentation tests, antibiotic susceptibility testing. Obtained results were analysed and presented through tables and diagrams.