Background: Resistance to antibiotics is rising markedly. Factor which contributes to resistance is the rampant irrational use of antibiotics. The trend of prescribing antibiotics in intensive care units (ICUs) of eastern India is less explored. Aims and Objectives: The aim of the study was to describe and analyze the utilization of antibiotics as per the WHO/INRUD prescribing core indicators in an intensive and critical care unit (CCU) of a tertiary center in eastern India. Materials and Methods: A prospective observational study was carried out on prescription pattern of antibiotics. Case records of patients with restricted antibiotic therapy were reviewed and evaluated using descriptive statistics. A total of 353 prescriptions were evaluated and analyzed. Results: Among the total 353 patients most common age group admitted was 41–60 years. Males were more in numbers. Myocardial infarction and post-operative complications were the most common cause of admission in ICU and CCU, respectively. Ceftriaxone (44%) and meropenem (37%) were the drugs used rampantly in ICU and CCU. More than 90% of prescriptions had injections and drugs were written in generic names. Almost 90% of patients in CCU had antibiotics in their prescription. Adverse events occurred in 14.7% of patients and thrombophlebitis was the most common adverse event occurred. Conclusion: The study has given us an overall impression of the antibiotics usage pattern in ICU and CCU of this teaching institution. The study has shown that antibiotics should be used judiciously in ICU and CCU. Policy can be made on the basis of the result of this study.