Iron supplementation can effectively control and prevent anemia in pregnancy. However, limited adherence is thought to be a major reason for the low effectiveness of iron supplementation programs.This research describes the factors influencing the adherence to iron/folate supplementation during pregnancy in Siem Reap and Kampong Cham provinces in Cambodia.Triangulation method, combining the quantitative and qualitative data collection methods, was performed for this study. A total of 177 women who gave birth during the year prior to the interview were selected for the quantitative survey. Ten women who gave birth during the year prior to the interview and 10 pregnant women were interviewed in-depth for the qualitative data.The ?2 test and binary logistic regression were used for statistical analysis. The findings showed an adherence rate of 47%. The logistic regression revealed that the number of supplements received, number of prenatal visits, and access to antenatal care were determinants of adherence (P < .05). In conclusion, access to and follow-up of antenatal care were considered elements essential to improve iron/folate supplementation. Community-based interventions, such as nutrition education and distribution of supplements, should be prioritized in the interventions to improve adherence in Cambodia.