In Mozambique, nutritional deficiencies are a major constraint to development. The present study assessed health providers' nutritional knowledge and practices in the national health system. The following were conducted: 30 interviews with health providers; 326 interviews with clients (129 with women attending prenatal consultations, 50 with women attending postnatal consultations, and 147 with mothers attending child consultations); and 190 observations of client-provider interactions (73 with pregnant women, 39 with post-partum women, and 78 with mothers attending child consultations). The findings of the study highlighted the extent of missed opportunities during routine prenatal, postnatal, and childcare consultations for the delivery of key services for the prevention and treatment of highly prevalent nutritional deficiencies among the children and women 'covered' by the health system. These findings can aid the development of policies and programmes aimed at strengthening the delivery of essential low-cost/high-impact nutritional services through the national health system in Mozambique.