In this study, Data Envelopment Analysis approach was used to analyze the energy efficiency of farmers, to find efficient and inefficient ones and to identify the wasteful uses of energy in kiwifruit production. Moreover, the effect of optimization of energy on improvement of input costs and energy indices was investigated. The results revealed that based on variable returns to scale model, 62.79% of growers were efficient, though, based on constant returns to scale model it was just 23.26%. The technical, pure technical and scale efficiencies of farmers were calculated as 0.942, 0.993 and 0.948, respectively. Total optimum energy requirement was found to be 26,604.11 MJ ha(-1); showing that 12.17% of input energy could be saved if the farmers follow the results recommended by this study. The contribution of chemical fertilizers input from total saving energy was about 78% which was the highest share. Optimization of energy use improved the energy use efficiency, specific energy and net energy by 13.86%, 12.17% and 22.56%, respectively. The results of economical analysis showed that optimization of energy decreases the total costs of production by 4.91%; and the benefit-cost ratio and productivity increased by 5.15% and 5.19%, respectively. (C) 2011 Elsevier Ltd. All rights reserved.