With population growing throughout the world, it is necessary to optimize water use especially in agriculture land. In order to determine water use efficiency (WUE) of cotton using micro irrigation system, a field experiment was conducted in the Agricultural and Natural Resource Research Institute of Orzoueyeh, Kerman province. The experiment was carried out in split plot design based on Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of crop water requirements (i.e. I-1 I-2 and I-3, that are irrigation based on 125, 100 and 75% water requirement, respectively) in main plot and two tape position as sub plot including conventional (r(1)) and alternative (r(2)) patterns. All treatments were assessed for productivity, water use and its efficiency, and economic issues, as well. The results showed that the yield obtained from I-1 was 379 and 1204 kg ha(-1) higher than that of I-2 and I-3, respectively. In addition, the obtained yield due to r(1) system was 377 kg ha(-1) more than in the r(2) pattern. However, interaction between treatments on crop yield indicated that the I(1)r(1) treatment resulted in the maximum yield. Despite of use water equality in sub plots, WUE in r(1) was 16% higher than in r(2). However, economic assessment exhibited that system cost in the r(2) in comparison with the r(1) was 11% lower.
