Crops water requirement under climate change effect in AL-Najaf city. CWR was predicted for three scenarios that were developed to anticipate the water requirements of crops in AL-Najaf governorate, Iraq under the effects of climate change. The prevailing situation at the time is called the reference scenario) (1988-2019a (, climate change scenario based on forecasted meteorological data from the GFDL-ESM2M model for two periods from 2020 to 2080 with 20-year steps (P1, and P2). To simulate the entire CWR and irrigation requirements for the current and future decades, the CROPWAT model (FAO, 1992) was utilized. Results employing both the GFDL-ESM2M models for periods (2020-2080) by one period (2020-2050) and the second period (2051-2080) demonstrate an increase in agricultural water requirements compared to the base climate. However, as a result of climate change, more irrigation will be needed in the future. Climate change, however, will result in a rise in irrigation needs in the future. Our findings indicate that the impact of climate change has resulted in a decline in agricultural output for important commodities like wheat and sorghum.