The main objective of this study was to describe economic and econometric analysis of cost functions of rain-feed barley production in the northern region from Syria and determine the economically efficient size and the profitmaximizing size, Primary data collected in (2010) through research interviews with farmers were used. Farms in the rainfed areas in. the northern region were divided according to stabilization zones (1, 2, 3 and 4), Through the descriptive economic analysis of costs of production of Farms in the rainfed areas in the northern region were divided according to stabilization zones (1, 2, 3 and 4), Through the descriptive economic analysis of costs of production of Barley, it was shown that the highest average cost of production of one dunum in the northern region was 1859.3 sp. in zone (1) and the lowest average cost of production of one dunum was 1694.5 sp. in zone (4), From the analysis of costs and returns, the results indicated that the highest net return (profit) in the northern region was 650.43 sp./dunum in zone (1), and the lowest net return (profit) was 395.2 sp./dunum. in zone (3) Also, the results of the descriptive economic analysis indicated that the lowest average cost of production of 1 kg of barley was 8.3 sp. in zone (1 and 2), and the highest average cost of production of 1 kg of oil was 9.3 sp. in zone (4), Using the econometric models of cost functions, the economically efficient size and the profit-maximizing size were computed and determined for each zone, indicating that farmers' practices were too far from these sizes based on the econometric analysis; namely the economically efficient size and the profit-maximizing size. Also the results indicated that the economically efficient acreage size was 35.8 dunum in zone (4), which was less than the actual area of this region.