Background and objective: Health care staff are at risk for hepatitis B infection the Hbs antibody levels will decrease by the time in vaccinated people.   This study was aimed to evaluate the level of Immunity in Health Care staff which were Vaccinated against Hepatitis B Virus in Kerman university of medical sciences university hospital during 2010-2011.   Material and Methods: In these cross-sectional study 452 health care staff vaccinated with hepatitis B including physicians, nurses and technicians who met inclusion criteria were involved the study by census method. Hbs antibody titre was quantitatively measured using ELISA method. Data were analyzed by descriptive statistics, mean, standard deviation and chi square in spss15 software.   Results: Of cases 253 (59.5%) were men and 172 (40.5%) were women. Anti-HBs Ab titers were 100 mlU/mL in 213 (50.1%) persons. The significant risk factors included male gender, age of 40 to 49 years, being a nurse, duration of employment in a clinical environment more than 5 years, and time duration after the primary vaccination exceeding than 10 years.   Conclusion: Base on the significant risk factors of hepatitis B virus infection among health care staff and because 14.1% of subjects had not protective levels of Hbs antibody titer, It is suggested that protective antibody levels to be measured after vaccination and revaccination should be performed as if required.