A Ph.D. thesis was discussed in the College of Agriculture, University of Tikrit on the economics of wheat production using production functions and transcendental costs under supplementary irrigation systems in Saladin Governorate for the agricultural season (2019-2020) by the postgraduate student, Mrs. Yusra Tariq Bakr Al-Bajari. The thesis reviewed that previous studies indicate a low efficiency of irrigation water in agriculture as a result of farmers’ tendency to waste in using water and that the bulk of the water is used for agricultural purposes to improve the efficiency of irrigation water use on the farm and reduce waste in the use of water. The thesis aimed at evaluating the use of mechanization in wheat farms and the comparison between the two complementary irrigation systems (fixed and pivotal) via using (CBA) and studying the weakness of wheat productivity for the water mechanize. The thesis recommended conducting economic studies and research on the subject of appropriate pricing for irrigation water via following a special policy to benefit from it in determining water prices for the needs of the farmer on the one hand and in a manner that serves the efficient use of water on the other hand.