Introduction: Antibiotics have a remarkable role in prolonging life, especially in underdeveloped and developing countries. Insufficient knowledge among doctors, peer pressure and patient demands, diagnostic uncertainties, lack of communication between the doctor, pharmacist and patients all implicate inappropriate antibiotic prescribing practices. Irrational antibiotic prescription can lead to antibiotic resistance, marking a global crisis. Aim: To evaluate the prescription pattern of antibiotics in the admitted patients of a tertiary care teaching hospital and assess the prescriptions' rationality. Materials and Methods: This was a retrospective record-based study done in the inpatients of Government Medical College, Manjeri, Kerala, India, for three months (1st October 2017 to 31st December 2017). Data was collected using a data collection checklist which included patient identity and demographic factors, name and route of the antibiotic prescribed, usage of multiple antibiotics, usage of prophylactic antibiotic, usage of generic names, adherence to National List of Essential Medicines (NLEM) and rational use. The data was analysed using Statistical Package for the Social Sciences (SPSS) version 16.0 and frequencies and percentages were determined for each variable. Results: Total 1,186 medical records were analysed, and 49.7% were prescribed antibiotics; 38.2% contained more than one antibiotic, and 64.8% contained parenteral antibiotics. Cefotaxime was found to be the most commonly prescribed antibiotic. An 88.3% of prescriptions were adhering to NLEM, and 29% contained generic names of antibiotics. Overall, 69 out of 589 (11.7%) were irrational prescriptions, and the use of multiple antibiotics with the same spectrum of coverage was found to be the most common reason for irrationality. Conclusion: In this study, the most drugs were prescribed from the NLEM. Cephalosporins were the most commonly used antibiotics for the inpatients in this hospital. Prescriptions with generic names of drugs were low. Irrational prescriptions contributed a minor percentage, and reserve antibiotics were too little.