Objective: Undernutrition is prevalent among pregnant women in Cambodia. The provision of fortified dietary supplements is one strategy to help pregnant women meet their nutritional needs. Corn Soya Blend Plus (CSBP) is a widely used prenatal dietary supplement in areas with high rates of undernutrition and food insecurity. However, little is known about its acceptability during pregnancy. The present study aimed to identify factors that affected the acceptability and consumption of CSBP supplements among pregnant women. Design: Women completed a structured interview designed to provide information on facilitators of and barriers to utilization. In addition, six focus groups were conducted with a subset of women (n 70) to further explore attitudes, perceptions and experiences related to CSBP use. Setting: Two districts in Kampong Chhnang Province, Cambodia. Subjects: Pregnant women (n 288) participating in a cluster-randomized trial of CSBP. Results: The acceptability of CSBP was influenced by sensory attributes, family support, peer influences, and attitudes related to diet, nutritional status and weight gain in pregnancy. Attaining adequate nutrition was considered less important than other concerns during pregnancy, particularly anxiety related to the costs of delivery and postpartum care. Acceptance was lower among new mothers due to fears of weight gain. Health benefits were common reasons for continued use and minor side-effects, such as nausea, were not major barriers to consumption. Conclusions: CSBP was generally well accepted in this population. However, organoleptic factors and perceptions regarding nutrition and weight gain in pregnancy, particularly for first-time mothers, were barriers to increasing acceptance among Cambodian women.