Abstract: Productivity refers to the rate of production on a unit area basis. The total amount of solar energy converted to chemical energy by green plant is gross primary production. For the estimation of primary productivity of Bay of Bengal at Chandipur coastal area of Odisha, the light dark oxygen method was followed. Seasonally, the minimum GPP was recorded in monsoon and maximum GPP during summer. On monthly basis minimum value was observed in July and maximum in May. The higher value of GPP and NPP respectively during summer may be due to penetration of more light into water body.