Iraq is one of the riparian countries within basins of Tigris-Euphrates Rivers in the Middle East region. The region is currently facing water shortage problems due to the increase of the demand and climate changes. In the present study, average monthly water flow measurements for 15 stream flow gaging stations within basins of these rivers in Iraq with population growth rate data in some of its part were used to evaluate the reality of the current situation and future challenges of water availability and demand in Iraq. The results showed that Iraq receives annually 70.92 km³ of water 45.4 and 25.52 km³ from River Tigris and Euphrates respectively. An amount of 18.04 km³ of the Tigris water comes from Turkey while 27.36 km³ is supplied by its tributaries inside Iraq. The whole amount of water in the Euphrates Rivers comes outside the Iraqi borders. Annual decrease of the water inflow is 0.1335 km³·year^-1 for Tigris and 0.245 km³·year^-1 for Euphrates. This implies that the annual percentage reduction of inflow rates for the two rivers is 0.294% and 0.960%, respectively. Iraq consumes annually 88.89% (63.05 km³) of incoming water from the two rivers, where about 60.43% and 39.57% are from Rivers Tigris and Euphrates respectively. Water demand increases annually by 1.002 km³, of which 0.5271 km³ and 0.475 km³ are within Tigris and Euphrates basins respectively. The average water demand in 2020 will increase to 42.844 km³·year^-1 for Tigris basin and for Euphrates 29.225 km³·year^-1 (total 72.069 km³·year^-1), while water availability will decrease to 63.46 km³·year^-1. This means that the overall water shortage will be restricted to 8.61 km³.