Domestic firewood collection is compared across study sites in Malawi and Tanzania. The study focuses on accommodation of infant-care within wood collection, the influence of family size on firewood demand and the contribution of girls to firewood collection. Malawian women carry their infants on wood collection trips. The Tanzanian women leave their infants behind. The shorter trips of the Tanzanian women, and the ready availability of alloparental care may facilitate this. Mean per capita wood consumption was similar across the two sites. However, a marked economy of scale was evident in wood use at the Malawi site. Girls at both sites assist with wood collection. Their contribution appears more than sufficient to compensate for their own wood use. Having a daughter therefore need not represent a net energetic cost to a woman in terms of firewood acquisition and consumption. While family size and structure appear to influence firewood consumption and acquisition, differences in the environment between the two sites may underpin much of the variation. The longer journey times, heavier load, and less frequent journeys undertaken by Malawian women may reflect the steep terrain and risks associated with firewood collection within a national park. © 2004 Plenum Publishing Corporation.