Four regression equations have been used to measure the effect of various factors on average yield, gross product, net product and net income in barley production in selected areas of Bulgaria. Out of five factors namely grading of land, agricultural machineries, seed, fertilizer and concentration of production, the first two factors were found to have significant positive effect on average yield. For gross product, grading of land and labour use had significant effect. In case of net product and net income, average yield was considered as one of the independent variables and it turned, out to be the most significant variable.