Abstract: Grb10 gene expression was analyzed in fetus and four organs during gestation process using the real-time RT-PCR and in situ hybridization. The real-time RT-PCR analysis result showed that the expression of Grb10 in whole em-bryos is throughout E8.5 to E19.5. The Grb10 gene expression level was gradually increased from E8.5 to E13.5, and then gradually reduced. The tissues specific expression levels were decreased in brain, heart, and lung from E12.5 to E19.5, but a peak expression was observed in liver at E18.5. Grb10 gene expression was also investigated at E13.5, E15.5, E16.5 and E18.5 sections by using in situ hybridization analysis. Strong signals of Grb10 were detected in brain, spine, kidney, and muscle tissues. These results suggest that Grb10 may play an important role during the development process in mouse.