The results of physical forcings on primary production, its variation and associated hydrography of the southwestern Bay of Bengal during the southwest monsoon (July) and post-cyclone period (November) of 1999 were studied as a part of Marine Research-Living Resources (MR-LR) assessment programme in the Indian EEZ. During the southwest monsoon coastal upwelling was prominent along 11°N (off Karaikal), whereas along 13°N and 15°N the signatures of upwelling were obscure. But in the post-cyclone period, the combined effects of well-mixed northwestern Bay of Bengal coastal waters and the freshwater injection from the land runoff associated with the cyclone brought nutrients to the mixed layer, which enhanced primary production along the southwestern Bay. A maximum of primary production (1229 mgC m - 2 d - 1 ), chlorophyll-a (24.4 mg m - 2 ) and particulate organic carbon (68.7 g m - 2 ) was recorded along the coastal waters off Chennai (13°N) during this period.