Objective: To determine the vaccination status against hepatitis B virus among the medical students of Sir Syed college of Medical Sciences for Girls, Karachi and to highlight the purpose behind vaccination. Study Design: Descriptive and observational/cross-sectional Place and Duration of study: This study was conducted in Sir Syed College of Medical Sciences for Girls, Karachi from October 2011 to March 2012. Participants and Methods: A total of 250 medical students, 50 from each year were distributed questionnaires after verbal consent. The data collected was analyzed by using SPSS version 17.0. Results: Out of 250 students, 75.7% were vaccinated against Hepatitis B. The positive vaccination history was contributed mainly by the clinical years. Screening before vaccination was done by 46.2%, while post vaccination antibody status was determined by only a 9.2% of students. Most common reasons for getting vaccinated were risk of exposure and motivation. Whereas, lack of time and forgetting the dosage were reasons given for not getting vaccinated. Conclusion: Health education and awareness programs on consistent basis are required to enhance the awareness about the vaccination against hepatitis B virus in medical schools.