Aim and Objective: This study is aimed in determining the prevalence of different bacterial isolates and their antibiotic susceptibility pattern from the patients with respiratory tract infections. Introduction: Respiratory tract infection is one of the most widespread infections that can affect the individuals of all the age Groups and have serious manifestations. There is an emerging antibiotic resistance among the pathogens causing RTI’s that leads to therapeutic failures in these patients. So it is important to perform antibiotic susceptibility testing for the isolated organisms and development of appropriate antibiotic policies. Materials and Methods: A total of 190 samples were collected from the patients at the tertiary care hospital, Chennai for a period of six months. Result: Out of a total of 190 samples 152 were positive for microbial isolates. The predominant pathogen isolated in my study was Klebsiella spp 44 (29%) followed by Streptococcus spp 30 (19.7%), Pseudomonas aeruginosa 22 (14.4%), Enterococcus spp 14 (9.2%), Staphylococcus aureus 10 (6.6%), CONS 8(5.3%), Acinetobacter spp 7 (4.6%), Candida species 10 (6.6%), Proteus spp 5 (3.3%) and Escherichia coli 2 (1.3%) respectively. Conclusion: Clinicians should prescribe the drugs according to the susceptibility pattern after isolating the etiological agent of the infection and this will further decrease the mortality and morbidity due to the disease.