Costs and incomes of barley crop have been studied during 1997, 1998, 2001 and 2002 and durum wheat in 1999, 2000 and 2003, in a rotation (fallow - barley - vetch ­ durum wheat) in a semi-arid rainfed field, for three cropping systems, such as 'minimum input' system (with mouldboard ploughing, cultivator preparation, sowing and harvest), 'conventional' system (including chemical fertilizer and herbicide treatments) and 'organic' system (including organic fertilization and mechanical weed control). Results show that 'minimum input' system yielded high economic benefits (271 %), followed by the 'organic' system (266%), and the worse option was the 'conventional' system (100%). In the case of selling the harvest of 'minimum input' system to a higher price in an organic market, this system obtains greater margins (496%), and on the other hand, in absence of an organic price, the 'organic' system obtained similar results (103%) to the 'conventional' system (100%).