Aim: to examine the impact of the nationwide implementation of the Integrated Maternal Health Care Project on the attitude, cognition, and behavior of the women who were given the maternity health care by health facilities. Methods and materials: this quasi-experimental clinical trial was conducted on 824 women who referred to health facilities of Ray (402 controls) or Islamshahr (422 cases) during their 2-month postpartum period. As a part of the Integrated Maternal Health, health care providers working in health facilities were required to provide clients contemplating to be pregnant with predetermined face-to-face interview. During interview, clients were provided with information required for safe maternity. Women were also provided with a booklet containing health messages. Results: When we considered the potential confounding effects of age, income, education levels, and urbanization, mean score for knowledge of intervention group was 7.4 percent point higher than knowledge of control group (P value <0.001), mean score for attitude of intervention group was 1.9 percent point lower than those of control group (P value=0.041), and mean score for practice of intervention groups was 6.1 percent point higher than, that of control group (P value<0.001). Conclusion: We observed that the Integrated Maternal Health Care program effectively improved the knowledge and practice of the participant. Opposite findings were observed for attitude; that is attitude of the control group was more positive towards maternal care than was the attitude of the intervention group. The improvements observed were not substantial and there are many rooms for improving instruction methods.