P19 cells are pluripotent embryonal carcinoma cells and can be differentiated into neuronal cell type by treatment with retinoic acid (RA) and aggregation culture. Cannabinoids are the active components of Cannabis sativa and they have diverse pharmacologic activities, such as pain control, anti-inflammatory effects, neuro-protection effects and tumor regression. Cannabinoids also involved in neuronal proliferation, migration, differentiation and survival in developing brain. Here, we studied the role of cannabinoids on neuronal differentiation of P19 cells. Treatment with cannabinoids increased the neuronal differentiation induced by RA and also promoted transcriptional activity of neurogenin 1, key transcription factor for neuronal differentiation of P19 cells. These results suggest that the cannabinoids can accelerate neuronal differentiation of P19 cells.