Manzala lake is the largest costal lake east Nile Delta and is considered as one of the most dynamic ecosystems along the Egyptian coast on the Mediterranean Sea. It is ecologically and economically important due to biological diversity, valuable fish, and wild life resources. The lake has undergone a considerable reduction in surface area due to input from human activities. This costal Lake constitutes an estuarine environment with a very particular behavior. The purpose of this investigation is to measure the general hydrological parameters (salinity, temperature, pH, dissolved oxygen, nitrate, nitrite, ammonia, phosphate) and concentration of trace metals (Fe, Zn, Cu, Mn, Cd, Pb) at seven stations in the Lake during four seasons (Jan.-Oct. 2012). The salinity ranged between(0.55-36) depending on seasonal bases. The pH, dissolved oxygen, nitrate, nitrite, ammonia, and phosphate had weak relation with salinity. The temperature of the lake varied according to the seasons. The pH of water ranged between (5.2-8.8). Dissolved oxygen (DO) of the water decreased with temperature, and increased with photosynthetic activity of the producers. There was strong correlation found between both Fe and Mn concentrations with salinity while the concentration of Cd, Cu, and Zn showed negative correlation and salinity.The concentrations of the measured trace metal were found in the following order Fe > Mn > Cu > Zn > Pb > Cd. Metal concentrations in the water indicate an increase in the pollution load due to movement of fertilizers, agricultural water, prawn cultivation and Motor Boat operations. An immediate action from the stakeholders is required in order to protect the lake from further pollution.