A prospective study of the relationship between anthropometric indices and subsequent morbidity was conducted during 2 seasons in young children in an urban Gambian community. Children with low height-for-age at the beginning of the rainy season had a significantly higher prevalence of diarrhoea and fever during the next 4 months, even after controlling for the possible confounding effects of a range of social, economic and environmental factors. The association was weaker in the dry season. This indicates that the increased prevalence of symptoms among stunted children is not solely attributable to environmental factors, and suggests that impaired growth is associated with impaired host response to infection.