Introduction: An adverse drug reaction (ADR) is any undesirable effect of a drug to the patient beyond its anticipated therapeutic effects while used clinically. Aims and objective: To analyze the incidence of ADRs in a tertiary care hospital reported from April 2015 till December 2017. Materials and methods: Two hundred ADR forms were included in the study and analyzed. These were codified into various drug classes according to anatomical therapeutic chemical (ATC) classification based on WHO–ATC Index 2019 besides categorized into preventable or not modified Schumock and Thornton scale. Severity was assessed based on a scale by Hartwig et al. Also, the ADRs were classified based on MedDRA 13.01 to system organ class (SOC) and preferred terms (PT) falling under respective SOC. Results: Maximum ADRs were reported by dermatology. Most commonly, it involved gastrointestinal system (GIT) followed by skin. Antibiotics and anti-cancer drugs caused maximum ADRs. About two-thirds were classifiable as moderate to severe, whereas about one-third were preventable. About 10% of cases were such that left deep impact of sequelae or were not recovered and one case was fatal. Conclusion: Extreme vigilance by clinicians is of utmost crucial virtue in detecting, diagnosing, and reporting such ADR for continued drug safety monitoring.