The integrated postpartum care is the most important factor in the prevention and reduction of delivery complications. Despite the free services for pregnant women, mothers do not show their interest to use them as appropriate. Therefore, this research was carried out to determine the effect of training pregnant women based on health belief model (HBM) on increasing the use of postpartum health care. This research was an empirical study (before-after study) conducted on 90 pregnant women referring to healthcare centers of Hamadan. The participants were randomly divided into two intervention (n=45) and control (n=45) groups. The educational intervention in this research was based on HBM performed as lecturing and question/answering in four 1-hour sessions and presenting educational content as leaflet. A researcher-made questionnaire was used in 3 stages of before intervention, and immediately after intervention, and 2 months after delivery to collect data. The comparison of the two groups showed that the mean of knowledge and constructs of HBM (including perceived susceptibility, perceived severity, perceived benefits, perceived barriers, cues to action, and self-efficacy) as well as behavior of mothers after training had a significant increase in the intervention group compared to the control group. According to the obtained results, designing and implementing training programs based on health belief model can help promote mothers` behavior in postpartum care.