Lake Manzala is Egypt's largest lagoon and one of most important fishing sources in the country. The lake faces numerous environmental challenges that have an impact on its water quality. This study was conducted to assess some characteristics lake's water. Seasonal water samples were collected from three lake stations during the years 2020 (autumn, winter, spring, and summer). Water samples were collected and analyzed physicochemically as well as microbiologically. The findings revealed significant variations in water's physical and chemical properties, including : temperature (13.8°C in spring -34.3°C in autumn), pH (9.09 - 6.2), dissolved oxygen (1.01 -14.66 mgl^-1), total dissolved solids (408-260 mgl^-1), total suspended solids (288-72 mgl^-1), ammonia (0.02 -6.15 mgl^-1), nitrite (0.39 -0.013 mgl^-1), nitrate (0.22 - 2.6 mgl^-1), T.phosphate (2611-1395.5 mgl^-1), Fe (214-35 mgl^-1), Mn (7.3 -66.7 mgl^-1) , Cu (1.02 -5.46 mgl^-1), Pb(1.01 -9.9 mgl^-1), Cd(1.01-9.9 mgl^-1) and  Zn (16.8 -45.4 mgl^-1). The findings indicate that the lake's water quality is critical. The results also revealed a high density of total viable bacterial count and indicator organisms such as total viable bacteria, faecal coli forms, Aeromonas spp < /em>, and Total coliform bacteria. It is concluded that water in Lake Manzala is highly damaged and the phenomena need more attention in order to reduce the pollution load that reaches the Mediterranean Sea.