Objectives:The purpose of this study is to examine the effects of venlafaxine, one of novel antidepressant drugs, on neurite growth in PC12 cells. Methods:PC12 cells were cultured with NGF for eight days. Then different concentrations($0{mu}M$, $1{mu}M$, $5{mu}M$) of venlafaxine were mixed with cultured PC12 cells. After 24 hours and 48 hours of culture, we compared the effects of venlafaxine on the total length of neurites of cultured PC12 cells between no venlafaxine treated group($0{mu}M$) and venlafaxine treated groups($1{mu}M$ and $5{mu}M$). Additionally, we studied the concentration-dependent effect of venlafaxine on differentiation in PC12 cells. Results:Experimental results showed that 1) the mean length of neurites in $1{mu}M$ and $5{mu}M$ venlafaxine treated group was more increased than no venlafaxine treated group(p=0.002). 2) the length of neurite in $5{mu}M$ venlafaxine treated group was more elongated than $1{mu}M$ venlafaxine treated group(p=0.046). 3) the length of neurite in $6{mu}M$ venlafaxine treated group was more elongated than all the other concentrations in our experiment. Above $6{mu}M$, the length of neurite was shortened in inverse proportion to the concentration of venlafaxine. Conclusions:This results suggest that venlafaxine, one of novel antidepressant drugs, promotes the differentiation of neuron. This study is believed to be a first step toward understanding the molecular and cellular mechanisms of antidepressant treatment.