The contribution of various factors to malnutrition, particularly stunting, may differ among areas and communities. This cross-sectional study aimed to estimate the level of malnutrition and identify factors associated with the high level of stunting in breast-fed infants aged 5-11 mo living in Dodota-Sire District, Ethiopia. Infants (n = 305) and their mothers were examined physically, and anthropometric and demographic data were collected. The content of zinc, calcium and copper in breast milk was measured, and data collected on the type, frequency of consumption, and time of introduction of supplementary feeding. Overall, 36% were stunted, 41% underweight and 13% wasted. The highest prevalence of malnutrition was seen in infants aged 9-11 mo. Among mothers, 27% had chronic energy deficiency (body mass index, <18.5 kg/m(2)) and 20% were night blind, indicating that vitamin A deficiency was a serious problem. Infants fed >3 times/d, consuming >600 mL/d or consuming cow's milk in addition to cereals and/or legumes had markedly higher length-for-age Z-scores than their peers fed less frequently, consuming less food or not consuming cow's milk [differences: 0.39, 95% confidence interval (CI): 0.04-0.74; 0.17, 95% CI: 0.02-0.32; 0.40, 95% CI: 0.07-0.72, respectively). Infants of mothers with low concentrations of zinc in their breast milk were more stunted. In conclusion, the quality and quantity of foods consumed by infants is insufficient to prevent stunting. Thus it is necessary to increase the nutrient supply to infants by increasing intake and nutrient concentration of breast milk and of supplementary foods they consume, and by providing supplements to infants where appropriate.