The effect of seasonal changes in household food availability on the dietary intakes and the nutritional status of 24 lactating women from smallholder rural households in Nakuru district Kenya, were investigated over a 15-month period in 1992/93 agricultural cycle. Dietary intakes and body weights were measured on monthly basis. Significant seasonal differences were found in intakes of calcium, vitamin A, vitamin C, riboflavin, and niacin respectively (P<0.01), as well as in the intake of protein, iron, and thiamin (P<0.05), but not with energy and fat intake. Large interseasonal weight losses of 5.6 kg (about 9%) at the rate of 1.1 kg/month, were observed between baseline measurements and the peak of the lean months when the energy intakes were 36.7 kcal/kg/day and protein at 1.1 g/kg/day. About 50% of the lost weight (2.8 kg) were recovered during the harvest months of January and February, when energy intakes improved to 41.0 kcal/kg/day, and protein to 1.2 g/kg/day. However, further weight losses of 1.6 kg or 0.5 kg/month occurred in the immediate postharvest months between March and June. While much of the weight loss may have been due to reduced energy intake during periods of food scarcity, part of the lost weight may have been due to increased energy requirement as a result of lactation and to increased physical activities. Further investigations are recommended.