We describe the incidence of some childhood infections in drought prone areas of southern Ethiopia. Our results are based on 24 months' biweekly observations of 828 children aged 0–5 years in the pastoralist community of Dubluk and the agricultural community of Elka. An average of 23% of the children in Dubluk and 13% in Elka were sick during any 2–week period. Diarrhoeal diseases represented the main cause of morbidity, but the yearly number of diarrhoeal episodes were lower than previously reported from Ethiopia. Respiratory tract infections and to a lesser extent diarrhoeal diseases, showed highest incidence rates during the main dry season. The highest incidence of lower respiratory tract infections coincided with an outbreak of measles. In Dubluk, children who lived near to the wells had higher incidence rates than those who lived further away, probably reflecting the importance of crowding on transmission rates. In Elka, literacy of mothers was associated with reduced incidence of both diarrhoeal and respiratory tract infections, whereas the use of open pit latrines was associated with increased diarrhoeal incidence. The decline in disease incidence in this region during the last months of our study may reflect an improvement of nutritional status.