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Objective: Ultrarapid freezing method (vitrification) is an altative method for cryopreserving ovarian tissue. The feasibility of intact murine ovaries cryopreservation was studied by vitrification. Methods: Intact mouse ovaries were cryopreserved using vitrification method and slow freezing method. The morphological alterations after frozen-thawed procedure and the apoptosis rates of primordial follicles were evaluated by histological examniation and TUNEL technique, and transmission electron microscopy (TEM) was used to observe the ultrastructural changes. Results:The percentages of normal primordial follicles in frozen-thawed groups were significantly lower than that in the control group ( P＜0.001), while no statistical difference was found between vitrification group and slow freezing group (78.37%±4.34% vs 78.82%±3.13%). Moreover, the distribution of abnormalities (nucleus, cytoplasm, and nucleus and cytoplasm) was similar (P＞0.05) in these two groups. In the vitrification group, slow freezing group and the fresh control group, the percentages of the TUNEL-positive follicles were 16.37%, 13.29% and 21.36%, respeetively. The apoptosis rates in the two cryopreservation groups showed no significant difference ( P ＞ 0.05). After the freezing-thawing procedure, subeellular structure was well preserved in both freezing groups with smililar ultrastructural changes. Conclusion: Vitrification is a convenient and efficient approach for small ovarian tissue cryopreservation.