This study determined the economical rotation of eucalyptus plantation in consortium with agricultural cultures and with pasture; analyzed the effect of the aggregation of value to forest products on the economic viability of the consortium; analyzed several sceneries for testing the effect of changes in wood proportion for sawmill and energy, prices and productivities of the products of the agro-forestry system. A cash flow was elaborated based on annual cost and revenue data of the agricultural cultures, pasture and eucalyptus plantation. To find the economical rotation and to accomplish the analyses of economical viability, Net Present Value amethod (VPL) and Equivalent Periodic Benefit were used, calculated at 10% interest rate per year. The economical rotation of the eucalyptus plantation was found to be between 6 and 9 years, depending on the site. There was a significant increase in the economical viability of the agro-forestry system, as if the forest products were added. The economical viability of the system depends more on the forest activity and on the livestock than of the agricultural annual activities. There was a larger tolerance to the variations in the prices and in the productivities of soybeans and rice.