SummaryThe stomach contents ofLemniscomys striatusandPraomys (Mastomys) natalensis, caught in the Rwenzori National Park over a period of one year (1965‐66), were analysed. InLemniscomysthe percentage by weight of insects (mainly termites) in the stomachs increased during the wet seasons, while termites were consumed byPraomysthroughout the year. Qualitative analysis showed that the fruits of the woody shrubErythrococcusformed an important part of the dietof Praomysduring the rains. Both species ate grass leaves and stems in varying amounts throughout the year and both utilized seeds of legumes and other herbs towards the end of the wet seasons.In bothLemniscomysandPraomyscollected between January and June 1972 liver and total body fat levels appeared to be related to rainfall and to reproductive state. There was a peak in fat levels during the high rainfall period in April. Pregnant and lactating females were caught mostly in May and June towards the end of the wet season; they had higher fat levels than males caught in the same period, but lower fat levels than non‐breeding mature or immature females and males caught in April.The possible significance of seasonal changes in diet and in body composition in the timing and duration of the breeding season is discus