Although Iraq is one of the affluent countries of water due to the multiplicity of sources of water, and high per capita availability of water in it and the estimated (2500 m3/ year), but the water supply in Iraq Suffers from fundamental problems of serious futuristic proportions, the most important of it is the adoption of this presentation on surface water coming from neighboring countries, especially in the absence of binding agreements that govern the rights of each side in these waters, as well as poor coordination with these countries with regard to its water policy, The effects of that reflected as a decline in the quantity and quality of water coming from abroad over time. As well as the adoption of internal water supply on precipitation, which is characterized with oscillation from year to year as well as the failure to achieve the best use of other sources such as ground water And non-traditional sources, and twice the storage capacity, and high wastage rates All these factors indicate real problems experienced by water in Iraq and the results of which was the survival of large areas Of arable land without exploitation, either with regard to the demand for water in Iraq, the agricultural sector is the largest consumer and in line with the global trend in water modeling . Due to the lack of studies in this area at the Arab level and local levels as well as the importance of knowledge of precise estimates about the supply and demand for water and the factors affecting them and the future expectations for the two .In order to activate the development plans and put the present and future national programs and strategies we have chosen this research which Contains identifying factors affecting the water gap in Iraq and relying on data from time series for the period (1980-2005) and try to reach estimates of water supply and demand functions in Iraq and then to future predictions for these functions till year (2030).