Chilika is one of the hotspots of biodiversity in India. It's part freshwater and part saltwater character, very high productivity and the presence of a variety of habitats in and around the lake allow the proliferation of an amazing number of species. Chilika is one of the terminuses on the migratory flyways and some of the largest congregations of aquatic birds in India can be seen here, particularly in winter. Because of high production rate, marine fish population find this spot to be a good breeding ground and growth of variety of fishes. The gross primary productivity (GPP) was varied between 22.4 and 187.9 mgC/hr/m3 covering 12 months among 15 different stations of Chilika lake. The highest was recorded at station 2 of May and lowest at station 6 of October. The monthly average productivity showed a clearly increasing trend towards summer months, where highest was recorded during May (131.3 mgC/m3/hr) and lowest dur- ing October (50.6 mgC/hr/m3). From the standard deviation values (monthly), it was observed that spatial variation (among stations) were not many differences among 12 different months. The high productivity during April-June reflected high phytoplankton abundance in Chilika lake water. CR has very good positive correlation with Chl-a (0.660, p>0.01), GPP (0.860, p>0.01), water temperature (0.264, p>0.01), turbidity (0.339, p>0.01), BOD (0.347, p>0.01), NO 3 (0.209, p>0.01) and PO (0.246, p>0.01). High negative relationships of NPP (-0.364, p>0.01), depth (-0.517, p>0.01), 4 transparency (-0.325), pH (-0.195, p>0.01), DO (-0.217, p>0.01) with CR established by the Pearson's correlation matrix. The water temperature plays and accelerate role in regulating net production capacity in a lake ecosystem. The pH, DO and nutrients were also playing vital role for regulating NPP and GPP values. A weak positive correlation between NPP and GPP proves moderately health of the lake ecosystem. It was established that higher production was not governed by a single factor or single water quality parameters. There are several environmental factors acting simultaneously which must be taken in to consideration while evaluating the production capacity of an aquatic ecosystem.