This article investigates the long- and short-term determinants of child nutritional status in the Malawian district of Salima. On the basis of monthly data from July 2004 to June 2012, the study adopts as explanatory variables a set of indicators representative of the following: household food security; maternal and child care; access to and coverage of health services; and health environment and services. Two models are estimated by Ordinary Least Square in order to compare results based on historical series and their trend-cycle, seasonal and irregular components. Findings highlight the value of a multidimensional food security indicator and the relevance of seasonal events and climatic shocks to child malnutrition. Implications for policy relate to the urgent need to arrest the long-term cycle of food insecurity and malnutrition and the differential response of child nutritional status to policies on food and health.