This study was conducted in Tajoura area. It is aimed to identify the effect of some pollutants on groundwater quality and to evaluate its suitability for drinking and irrigation. The results of this study were compared with those obtained by previous one which was carried out 10 years ago for the same wells and also with the standard of Libya 1992. To achieve the objectives of the study, 35 samples of groundwater were collected from wells within the selected area during April 2008. For comparison purposes, one sample was taken from the wastewater treatment plant lagoon. Many chemical and biological analysis have been performed. The chemical analysis was carried out to determine the Electric conductivity (EC), pH, Total Dissolved Solid (TDS), Na­⁺_­ , K⁺, Ca⁺², Mg⁺², Cl^-, HCO₃^-, SO₄^-2 , NO₃^-, Sodium Adsorption Ratio (SAR) and Residual Sodium Carbonate ( RSC). Heavy metals like, Pb ,Cr,  Fe, Cu , Zn , Ni and Cd were also determined. The biological analyses were also performed to investigate the presence of Total Coliform andEscherichia coli in the water samples.  The results showed that most of the study area is highly affected by the wastewater and seawater intrusion. In addition, the results proved that the concentration of Total Dissolved Solid increases towards the north whereas it reached to more than 3400 mg/l in some water samples. It has been noted that some water samples are chemically suitable for drinking and irrigation usage. On the other hand, the highly presence of Total coliform and Escherichia coli in the water indicated that the wells were exposed to sanitation which emerged from wastewater. The water samples which taken from Bir Austa Milad area were found to be suitable for drinking and irrigation according to Libyan standards 1992.. Such results revealed that Bir Austa Milad area located quite faraway from the indicated pollution sources.