Donor deferral results in loss of potential, motivated blood donors, and thereby, availability of blood for needy patients. This study analyses the frequency and reasons for donor deferral, including high hemoglobin deferral, which is underreported in India. Methods: Retrospective analysis of the deferral record of whole blood donors from January 2014 to December 2018 was performed with respect to the pre-donation screening process at our center. Accordingly, the deferrals are categorized as stage1-evaluation of Donor History Questionnaire (DHQ), stage 2-medical examination, stage 3-hemoglobin (Hb) check using copper sulfate method or a gradually implemented quantitative hemoglobin analyzer, and stage 4-before phlebotomy. Donor demographic details, donation frequency, and deferral reasons were noted. Descriptive statistical analysis was performed using SPSS version 20 (IBM, USA). Results: Of 99,680 pre-donation screenings, 10.6% was deferred. The highest deferral (56.02%) was at stage 3 (based on hemoglobin level) contributed by low (52.45%) and high (3.75%) hemoglobin deferrals against cutoff of 12.5 to 18 g/dl. High Hb was noted only in male donors when screened by hemoglobin analyzer. Further, a steady fall in low hemoglobin but a rise in high hemoglobin deferral rate owing to the gradual implementation of hemoglobin analyzer over the study period was noted. The deferrals in stage 1, 2, and 4 were 29.64%, 13.97%, and 0.36%, respectively. Overall, the deferral rate was higher in females (49.88%), and in first-time (13.63%), and 18 to 25 yrs age-group (4.25%) donors for low Hb, underweight, and tattooing/ear piercing. Conclusion: Insights on donor deferral reasons promote proactive measures towards donor recruitment and retention. Further, donor hemoglobin screening by quantitative method, if followed uniformly by all blood centers across the country, will help identify the true prevalence of high hemoglobin in Indian blood donors and ensures donor safety.