Background and Objective: To study the effect of deprenyl on neuroprotective or survival on motoneuron and on gliosis reaction.   Materials and Methods: Sprague Dawley rats (250-300 gr) of Razi institution were used to determine the effect of deprenyl (2.50 mg/kg ) on neuroprotective or survival on motoneuron and on gliosis reaction through morphometry and immunohistochemistry methods.   Results: The results are divided into two parts:1- the result of morphometry for motoneuron.2- Astrocyte and oligodendrocyte count and their percentage. After spinal cord compression, motoneuron in ventral horn decreased with cavitation. While,the changes in study group (deprenyl ) is less than control group( normal saline) one of the groups that had taken Deprenyl for 4 weeks revealed less changes so, after 4 weeks, the neuroprotective effects of Deprenyl increased (P≤ 0.05). In addition, Deprenyl had also decreased the gliosis reaction .It was even more effective after 4 weeks (P≤ 0.05).   Conclusion: For the first time, Deprenyl effect was studied in gliosis reaction. It seems that it decreased the number and percentage of astrocyte and became more effective after 4 weeks.By the way it needs more research to find the effect and mechanism of deprenyl in different dosage.