Abstract: The physicochemical and microbiological water quality parameters of Lake Sagara in the Malagarasi ecosystem, Tanzania, were studied between September 2003 and January 2004. Standard methods of analysis were used to elucidate the levels of the main water quality parameters. The Lake was found to be shallow (maximum depth 6.5 m) with encroaching hydrophytes and floodplain grasslands. High turbidity values ranging from 20-126.5 NTU recorded in the studied sites was attributed to vigorous wind mixing of the Lake water. The temperature, pH and chlorides values were 24.4-27.0�C, 6.8-8.8, 7.9-17.4 mg L^-1), respectively. These values are within the standard water quality requirements. The values of conductivity (89-212 ìs/cm), phosphates (1.0-4.5 mg L^-1), organic nitrogen (0.8-2.2 mg L^-1); abundant sediments and algal blooms suggest that Lake Sagara is eutrophic. Values of dissolved oxygen (6.2-7.3 mg L^-1), COD (22.1-42.6 mg L^-1) and BOD (3.8-7.1 mg L^-1) show that so far, the levels of oxygen-demanding wastes in Lake Sagara can still sustain aquatic life. The high counts of enteric pathogenic microorganisms including fecal coiliform (10-66 MPN/100m), Vibrio sp. (2-6 CFU mL^-1) and Salmonella sp. (1-4 CFU mL^-1) as a result of surface runoff and direct contamination depict poor hygienic practices by the local fishermen and the surrounding communities. This work provides the first ever scientific research on the microbiological status of Malagarasi-Muyovozi wetland ecosystem.