While conventional farming systems face serious problems of sustainability, organic agriculture is seen as a more environmentally friendly system since it favours renewable resources, recycles nutrients, uses the environment’s own systems for controlling pests and diseases, sustains ecosystems, protects soils, and reduces pollution. At the same time organic farming promotes animal welfare, the use of natural foodstuffs, product diversity and the avoidance of waste, among other practices. However, the future of organic agriculture will depend on its economic viability and on the determination shown by governments to protect these practices. This paper performs panel regressions with a sample of Catalan farms (Spain) to test the influence of organic farming on farm output, costs and incomes. It analyses the cost structures of both types of farming and comments on their social and environmental performance.