Background: Hepatitis B virus infection is one of the major causes of chronic liver disease. The prevalence of chronic hepatitis B virus infection in India is 1.46% with an estimated 17 million people who are chronic carriers of Hepatitis viral infection. Seroprevalence of HBV infection is few times higher among health care workers when compared to the general population. Objectives: To assess the knowledge and perceptions of first year medical students regarding HBV infection and vaccination. Methodology: This cross sectional study was carried out among first year MBBS students belonging to 2016-17 batch of Sri Siddhartha Medical College, Tumkur, Karnataka. A self structured objective type of questionnaire was prepared consisting of questions which were used to assess the knowledge regarding HBV infection and vaccination for it. The responses were analyzed using Microsoft excel and Epi Info 7. Results: 92.3% of the study population told that they have heard about hepatitis and 78.46% were also aware that the primary organ affected in hepatitis is liver. 87.69% responded that they were aware of hepatitis being transmitted from person to person. 89.23% of the study population had correct knowledge about the mode of transmission. Conclusion: It is recommended to increase the awareness of importance of vaccination against HBV at the beginning of the medical course and consider to vaccinate all of them before they are exposed to the patients during their clinical postings.