In this study we evaluate potential impacts of an income guaranty program (PGR) that could be established as an alternative use for funds from Brazil's National Family Agriculture Strengthening Program (PRONAF). Using Newbery and Stiglitz methodology, we analyze the effect of PGR upon the incomes of rice, maize [com], bean, and cassava producers and on the supplies and prices of these commodities. This methodology is well adapted to our study, as we include an analysis of risk-aversion and credit financed capital investment. Our results show that family farmers producing rice, maize, beans and cassava would obtain income gains on average of 38%, 35%, 62%, and 49% for their respective crops. The income gains arise from an increase in the average pricesreceivedof21 %, 24%, 30%, and29% and an increase in average production of 8%, 4%, 12%, and 4%. The results also show that consumers would be benefited by a resultant reduction in the these commodities average prices: 31 % less for rice, 29% less for maize, 34% less for beans, and 32% less for cassava. It is found that over the last analyzed year, 1997, the total cost of PGR would have been R$ 1,634 million while the social cost would have been R$ 47.5 million, or 2.9% of the total Income Guaranty Program's total cost.