Ascorbic acid (AA) as a vitamin and neuromodulator is present in most parts of CNS such as nucleus accumbens shell (Acbsh). This study evaluates the effect of intra-nucleus accumbens shell injection of AA on spatial learning and memory. 35 adult male Wistar rats (220-270 g) were divided into 5 groups: control (intact), sham AA (injected normal saline as AA vehicle) as well as 3 groups of AA (12, 24 and 48 μg/rat/side). After one week of recovery injections were performed. Thirty minutes after each injection the rats were trained in the Morris Water Maze (MWM) and spatial learning and memory parameters were recorded and then analyzed. The results showed that AA at the dose of 48 μg/rat/side significantly increased the travelled distance and latency time to reach the hidden platform in comparison with either control or sham groups (p<0.001). Intra-Acbsh injection of AA led to deficiency of spatial learning.