Purpose: We carried out this study to evaluate the biological significance of phospholipase C BI gene mutation in mouse sperm in the acrosome reaction, fertilization, and embryo development. Methods: Study subjects were divided into two groups according to the sperm [intact phospholipase C (PLC) beta1 and PLC beta1(-/-) C57BL/6J x CBA F-1 mouse sperm] used. The positive acrosome reaction rate labeled with fluorescein isothiocyanate-Pisum sativum agglutinin, the fertilization rate, and the rate of embryos developed to the stage of morula or blastocyst in the two groups were compared. Results: The mouse sperm null for the PLC BI gene showed a lower acrosome reaction rate than control sperm (69.2 vs 50.9%, P < 0.05). And the fertilization rate and the rate of embryos developed to the stage of morula or blastocyst were also lower in the group using PLC beta1(-/-) mouse sperm compared to the intact group (P < 0.05; 73.5 vs 51.8% and 15.7 vs 4.3%, respectively). Conclusions: Mutation of the PLC beta1 gene in the mouse sperm reduces the acrosome reaction rate, fertilization rate, and embryo development rate, which may be the etiologic factors responsible for the low reproductive rate of PLC beta1(-/-) mouse.