The Al-Hassa oasis at the Kingdom of Saudi Arabia is an agricultural area depends on irrigation associated with a drainage network with three main drainage canals. Two of them, the D١ and the D٢, cover most of the oasis total area (٢٠،٠٠٠ ha) while the third one (the D٣) covers a limited area. This study aimed to examine the spatial variability in the concentrations of NO٣ - and PO٤٣- in the drainage water of the D١ and the D٢ canals.