Context: Health care professionals including medical students face a high risk for Hepatitis B transmission. Hepatitis B vaccination is routinely administered to health care providers and medical students. However due to the rigors of medical training, medical students miss doses of the vaccine. There is scant research on immune response following delayed immunization schedule. Aims: To compare immune response as measured by anti-HBsAg antibody levels in medical students who followed delayed and standard vaccination schedule of Hepatitis B vaccination. Settings and designs: A cross sectional comparative study was conducted among randomly selected 50 medical students of a medical college in Chennai. Methods and Materials: Data on demographics, Hepatitis B immunization details and other covariants were collected. A two step immunoassay, using Chemiluminescent Microparticle Immunoassay (CMIA) technology was used for the quantitative determination of anti-HBs in human serum and plasma. The collected data was analyzed using statistical software IBM SPSS Statistical Package version 21. Results: Of the students, 36 (72%) were females and 14 (28%) were males. Among the participants who followed standard immunization schedule without delay, 6.3% had poor immune response, and 12.5% were hypo-responsive. Among the participants who followed delayed schedule, 2.9% were non-responsive and 5.9% were hypo-responsive. After adjusting for age, gender, BMI and delay in schedule, it was found that greater gap between dose 1 and dose 2(p = 0.001) and gap between dose 2 and dose 3(p = 0.004) significantly influenced the anti-HBsAg antibody titres. Conclusion: It is seen that a delayed or altered vaccination schedule did not seriously affect the immune response among medical students. Therefore, the focus should be on completing the immunization schedule of Hepatitis B at the best available opportunity.