Hepatitis B remains as one of health problem in the world. The results of several studies related to factors in predicting of timely hepatitis B immunization were still inconsistent. Aim of this study is to identify determinant of timely hepatitis B zero dose immunization in East Lombok. We used cross sectional design study derived from immunization coverage survey at six districts/cities in 2013. A Total of 227 children aged 12 to 23 months who already got immunization of hepatitis B zero dose and well documented were included as samples in this study. Timely immunization was defined based on the distance between time of birth and time of received hepatitis B immunization (zero dose) that is within 24 hours after birth. Data was analyzed using Chi-square and Logistic regression in multivariate level. The result of this study showed only 60.4% of children were get timely hepatitis B zero dose immunization. Mother’s behavior agains immunization program is the only factor that can predict the timely hepatitis B zero dose immunization (P-value 0.007 CI 95% 1.94-3.62). Meanwhile, other factors i.e. sex, socio-economic status, parent’s education, knowledge and attitude of mother and place of immunization service have not able to predict the outcome, statistically. The stakeholder should improve the optimal exsisting services, which will be impact to maternal behavior in immunization programe.