BackgroundThis study investigated the infant feeding practices of participating mothers who were recruited into a research project aimed at improving the nutritional status of mildly wasted children (< -1.0 to ≥ -1.5 Weight-for-Height Z-scores) aged ≥ 6 to < 60 months on Nias Island, Indonesia.MethodsCross-sectional, questionnaire-based interview of mothers of the index children (n = 215) who were admitted to the community program for mildly wasted children in the study area. Four focus groups and twenty in-depth interviews were conducted to explore further information on infant feeding practices in the study area.ResultsRetrospective results indicated that 6% of the mothers never breastfed. Fifty two percent of mothers initiated breastfeeding within six hours of birth, but 17% discarded colostrum. Exclusive breastfeeding until 6 months of age was practiced by 12%. Seventy-four percent of the mothers offered supplementary liquids besides breast milk within the first 7 days of life, and 14% of infants received these supplementary liquids from 7 days onwards until 6 months of age. Moreover, 79% of the infants were given complementary foods (solid, semi-solid, or soft foods) before 6 months of age. About 9% of the children were breastfed at least two years. Less than one in five of the mildly wasted children (19%) were breastfed on admission to the community program. Qualitative assessments found that inappropriate infant feeding practices were strongly influenced by traditional beliefs of the mothers and paternal grandmothers in the study areas.ConclusionGenerally, suboptimal infant feeding was widely practiced among mothers of mildly wasted children in the study area on Nias Island, Indonesia. To promote breastfeeding practices among mothers on Nias Island, appropriate nutrition training for community workers and health-nutrition officers is needed to improve relevant counseling skills. In addition, encouraging public nutrition education that promotes breastfeeding, taking into account social-cultural factors such as the influence of paternal grandmothers on infant feeding practice, is needed.