Objective: Phosphatidylinositol (PI) has been suggested to have important functions in intracellular signal transduction and to be effective in improving brain function. However, its effects on memory and learning ability have not been elucidated. Therefore, in the present study, we aimed to clarify the effects of oral administration of 59% purified PI (PI 50) on memory and learning ability in rats. Methods: Wistar male rats were divided into four groups: (1) distilled water administration group, (2) 30 mg/kg PI 50 administration group, (3) 100 mg/kg PI 50 administration group, and (4) 300 mg/kg PI 50 administration group. Effects of oral administration of PI 50 on memory and learning ability were investigated using behavioral and molecular biological techniques. Result: In the learning and memory behavioral tests, the PI 50-administered group showed improvements in spatial memory and learning ability compared to the distilled water-administered group. Additionally, c-Fos- and BrdU-positive cells in the hippocampus increased significantly in the PI 50-administered group. The PI 50-administered group showed a significant increase in BDNF, PKC-α, and MAPK protein expression compared to the distilled water- administered group. Conclusion: These results indicate that PI 50 intake stimulates nerve cell activation and growth factor secretion in the hippocampus by activating the PKC-α and MAPK signal pathways, thus, facilitating the development and proliferation of nerve cells and may affect the enhancement of learning and memory ability. This study provides evidence that PI 50 may affect the enhancement of learning and memory ability.