Anthropometric measurements made on 470 individual children (age 0-18 years) from a seminomadic population of Datoga pastoralists living in northern Tanzania were used to describe patterns of child growth. Comparisons with reference growth curves derived from American samples suggest that pastoral Datoga children grow poorly in this region. Body compositional changes with age differed markedly from the reference population. There were negligible fat gains through childhood, even among females. Comparison with data on other East African pastoralists showed that population growth performance is intermediate between that of nomadic and settled pastoralists. Little catch-up growth occurs during childhood, and adolescence appears to be delayed among males. The results contribute to the growing database on health indicators for African pastoralists and suggest a need for further research to investigate mechanisms for growth stunting in these populations.