This chapter examines the roles of village size, exchange balance, and household demography as determinants of exchange patterns among the Yanomamo, an egalitarian horticultural people of the Venezuelan Amazon. It demonstrates that reciprocal altruism provides a perspective superior to that of generalized sharing to account for food exchange patterns among the Yanomamo. A theoretical alternative to egalitarian exchange is the theory of reciprocal altruism, which suggests that food exchanges are strategic in nature and are designed to enhance the fitness of the individual engaged in exchange. The method used to gather data on Yanomamo food exchanges follows a modified time-allocation technique first employed by Kaplan and Hill in their studies of Ache exchange. Exchange is intensive among the Yanomamo, it tends to be limited to a small fraction of households in the village. The positive correlation between giving and receiving among Yanomamo families leads me to conclude that exchange among the Yanomamo is balanced.