Background: In a society to improve medical facilities, one of the crucial parts is the availability of safe and good quality blood. The occurrence of adverse events during blood donation affects donor return. Aims and Objectives: To analyse the frequency and significance of adverse events during blood donation. Materials and Methods: This study was conducted for a period of one and a half years from 1st January 2018 to 30th June 2019 on 11,170 allogenic blood donors including both voluntary and replacement donors. The type and frequency of adverse events were recorded during blood donation. Results: 116 adverse events were recorded resulting in 1% adverse event rate, among which majority had vasovagal reaction 89 (76.7%), followed by hematoma formation 15 (12.9%), nerve injury 11 (9.5%) and rebleeding at the site of prick 1 (0.9%). Significant relation with female sex, younger age, low weight, donating in camps and first-time donors was noted. Conclusion: In existing scenario of shortage of blood in India, new and existing donors should be motivated to donate blood regularly by bringing down the events of adverse reactions during blood donation.