The aim of this study is to evaluate the association between co morbid disease and respiratory pathogen in patient with respiratory tract infections in a tertiary care teaching hospital and to assess the management pattern of respiratory tract infections. A prospective observational study was conducted in the different departments of karuna medical college and hospital, a tertiary care teaching hospital, Chittur, Palakkad.170 Patients were enrolled in the study.59.42% were for male patients and 40.58%were for female patients. Categorisation of patients based on age, 25.29%were given for the patient’s between18-40 years of age, 46.47% were given for the patients between 41-60 years of age and 28.24% were given for the patient between 61-80 years of age. Among 170 RTIs patients enrolled in the study, 20.58% were diagnosed with diabetes mellitus, 7.05% with hypertension, 2.94% with ischemic heart diseases and 1.76%with rheumatoid arthritis. Among 35 Diabetes Mellitus patients ,22.85%patients with Upper Respiratory Tract Infections and 77.15%patients with Lower Respiratory Tract Infections. 85.29% of patients were treated empirically and 14.71% were treated with targeted therapy. In this study reported a higher risk of lower respiratory tract infection in patients with diabetes.