Limnological investigations of Naujan Lake were conducted for a period of one year and five months to evalute its productivity. Studies were made on the lake’s physico-chemical and biological characteristics including the lake’s fisheries, using the monthly landings in the three existing landing points including catches from the only fish corral operating in the Results of the chemical analysis of the water showed a considerable amount of dissolved oxygen ranging from 4.9 to 8.5 parts per million; pH ranges from 6.0 to 9.8; carbon dioxide ranges from 0.8 to 2.0 and alkalinity had an annual mean reading of 145.4 to 162 as calcium carbonate, from surface to bottom. Visibility test ranged from 1 to 2.5 meters. Phytoplankton identified consisted of Cyanophyta, Cholorophyta and Chrysophyta while Zooplankton was represented by rotifers, copepods and cyclop. These indicate that the lake is highly productive as evidenced by a chemically active substrate and the presence of rich dissolved substances. The lake was found to be biologically active and showed signs of seasonal and spatial variations. The fish stock reflected a varying fair to large amounts of indigenous and migratory fish species present in the lake. A continuing program of research is indispensable for the lake’s development