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Introduction: Hepatitis B is one of the world's health problems and increased the risk of hepatocellular carcinoma and liver cirrhosis. Medical students exposed to risk Because of future job, and being infected than the general population. This study will Survey level of knowledge, risk perception and behavioral intention medical students about hepatitis B. Methods: This is a descriptive - analytical study and populations are students of Isfahan University of Medical Sciences. Sampling was randomly and sample size according to the formula: n= Z2 * S2/D2 were at least 385 people. Data were collected by questionnaire and were analyzed by using SPSS 18 software and statistical tests of Pearson, Spearman, t and ANOVA. Findings: 457 students (41.8% male and 58.2% female) in 29 fields of study participated in the study. Mean and standard deviation of students' awareness (5.56 ± 2.1), public risk perception (21.8 ± 3.12), perceived personal risk (7.25 ± 2), and behavioral intention of students (14.99 ± 3.28) is. Between risk perception and behavioral intention with gender, Knowledge and risk perception with age, Knowledge, risk perception and behavioral intention with students' education level was significantly related (P < 0.05). Conclusions: According to the high risk of medical students, seems that necessary to study barriers and causes of low behavioral intention and Also implement educational interventions.