Background: Hepatitis B (HB) is a major health issue in Bangladesh, with an approximated percentage ranging from 2-7% among the population of the country. HB remains a significant problem due to lack of awareness and inadequate knowledge regarding its transmission, prevention, and risk factors. Objective: To evaluate the current state of knowledge and perception regarding hepatitis B infection among the adult patients of Community Based Medical College Hospital in Bangladesh. Methods: This descriptive cross-sectional study recruited 90 adult patients at the Department of Medicine between July 2022 and June 2023. An interview survey using a structured questionnaire was used to gather data from the respondents. The data analysis was done by descriptive statistics means. Results: A larger proportion of the respondents were male (61.1%), within the age group of 26-35 years (30%), married (66.7%), and primary education (46.7%). Individuals who acquired their HB information from doctors were the highest at 38.9%. 4% were able to point out accurately that blood can transmit the virus, while 22.2% were still convinced that water could spread HB. As for the means of transmission, only 2% knew that it could be sexually transmitted. Only 9% knew about vaccination, but 22.2% of the respondents had the wrong perception that safe drinking water reduces the risk of getting HB. Doctors were most frequently reported as a high-risk group (38.9%), followed by drug abusers (27.8%). Conclusion: The findings of this study show that the study population has limited knowledge about hepatitis B and contains misconceptions about the means through which it spreads and the methods of avoiding it. The study emphasizes the imperative of designing effective health education interventions to fill these knowledge deficits with regards to transmission, risk factors, and vaccination coverage. They said that healthcare providers are very important in transmitting information and should ...............