Introduction: Apoptosis plays a crucial role in normal development of central nervous system. In fact, disregulation of apoptosis is the major pathophysiological mechanism of many diseases, such as Alzheimer's disease. The aim of this survey was to study the role of apoptosis in neuronal injury during Alzheimer's disease. Materials and Methods: The experiments were carried out in adult (6-7 months old) male Wistar rats (230-270 g) in 2 groups of sham and streptozocin (STZ). Animals in sham and STZ groups received normal saline and STZ intracerebroventricular (ICV) injections for two days, respectively. To assess neuronal apoptosis, 18, 45 and 90 days after STZ injection, TUNEL test was performed. Results: The result showed that apoptosis in hippocampal CA1 and CA3 areas were significantly increased in rats treated with STZ after 90 days. Also, there was a significant increase in the mean number of apoptotic cells in rats treated with STZ after 90 days compared to their age-matched sham group in the hippocampal CA1 and CA3 area. Conclusion: ICV-STZ injection in rats was resulted in significant neuronal apoptosis in the hippocampus.