Fluvoxamine maleate is a well established anti- depressant (SSRI). The memory enhancing activity was evaluated using elevated plus maze and Hebbs Williams Maze. Brain acetylcholinesterase, brain nitrite and plasma corticosterone levels were also estimated. Acute Immobilization Stress (AIS) was produced by immobilizing animals for 150 min. Fluvoxamine maleate and donepezil significantly showed memory enhancing activity in both unstressed and stressed mice. Fluvoxamine maleate significantly reduced brain acetylcholinesterase activity and brain nitrite levels in both unstressed and stressed mice. Fluvoxamine maleate significantly reversed scopolamine-induced amnesia in unstressed and stressed mice. 7-nitroindazole and aminoguanidine significantly enhanced memory improving activity and brain nitrite decreasing effect of Fluvoxamine maleate in unstressed and stressed mice respectively. Plasma corticosterone levels were significantly decreased. Thus it showed memory enhancing activity in unstressed mice by decreasing brain AChE activity and inhibition of neuronal NOS. The memory enhancing activity in stressed mice was due to decrease in brain AChE inhibition of inducible NOS.