Abstract
FAO-56 Model, which is widely used in the world, was used to estimate the net Radiation (Rn) in 19 weather stations spread in IRAQ for the time period (1980-2008). Linear Regression Equations were found for Iraq between the mean monthly values of (Rn) and the mean monthly values of: Extraterrestrial Radiation (Ra), Total solar radiation(Rs), Net Short wave radiation (Rns), Net Long wave radiation (Rnl), Sun shine ratio (n/N), which gives a correlation coefficients ranged between (0.707-0.986). Multiple Regression Equation was found between the mean monthly values of (Rn) and the mean monthly values of all the following climatic elements [RH, Tmin, Tmax, Rs] for Iraq which gives a highly correlation coefficient reach (0.999).