Traditional historiography describes the repartimiento de mercanc'as as a forced system of production and consumption in which officials of the Spanish crown compelled Mexican Indians to produce goods marketable in the Spanish economy and to purchase expensive and undesired Spanish products. The author challenges this conventional portrayal of Indian-Spanish economic relations by arguing that Indian market behavior was economically rational and voluntary. He further argues that the repartimiento was an institution designed to overcome market imperfections inherent in Mexico s colonial economy and to facilitate the extension of credit in a cross-cultural environment. Examining repartimiento production of cochineal, a dyestuff produced exclusively by Oaxacan Indians and representing Mexico s most valued export after silver, this study shows that Indians produced cochineal for the market voluntarily because it provided them with needed income. The primary role of the repartimiento was to provide Mexico s indigenous peasantry with credit, without which they could not have participated in the market as extensively as they did. Owing to the difficulty of collecting debts, credit provision was monopolized by agents of the Crown, the alcaldes mayores, who alone possessed the legal leverage needed to enforce the payment of debts. Though Spanish officials profited from the repartimiento, their economic gains were not so great as traditionally believed.