Objective MCM3, a component of the MCM complex (MCM2-MCM7 complex), plays a critical role in the initiation of DNA replication and is a marker overexpressed in most malignant tumors such as liver cancer.However, whether it is involved in the early development of zebrafish liver is largely unknown. Our current study addressed whether zygotic mcm3 contributes to the regulation of liver development in zebrafish. Methods Expression of zygotic mcm3 was examined using in situ hybridization. mcm3 was then knocked down by injecting a mcm3 MO, and the liver developmental phenotype was analyzed in transgenic line (fabp10: GFP) and wild type embryos. Results Being as azygotic gene, mcm3 was expressed ubiquitously before the bud stage, whereas it was highly restricted in somite, head andendoderm-related tissues from the somite stage. After mcm3 loss of function, the liver was smaller than that in the controlembryos, but no other distinct developmental defects were observed. In addition, mcm3 mRNA injection rescued the defectof liver development in the mcm3 morphants. Conclusion Zygotic mcm3 is involved in the regulation of early development of zebrafish lever.