Purpose: The Glycyrrhiza uralensis species (Leguminosae) as a medicinal biocompound, and one of its root components, isoliquritigenin (ISL), which is a flavonoid, has been reported to have anti-tumor activity in vitro and in vivo. However, its function in bone formation has not been studied yet. In this study, we tested the effect of Glycyrrhiza uralensis (ErLR) and baked Glycyrrhiza uralensis (EdLR) extracts on osteoblast proliferation, alkaline phosphatase (ALP) activity, and bone-related gene expression in osteoblastic MC3T3-E1 cells. Methods: MC3T3-E1 cells were cultured in various levels of ErLR (0, 5, 10, 15, $20{\mu}g/mL$), EdLR (0, 5, 10, 15, $20{\mu}g/mL$), or ISL (0, 5, 10, 15, $20{\mu}M$) in time sequences (1, 5, and 20 days). Also, isoliquritigenin (ISL) was tested for comparison to those two biocompound extracts. Results: MTT assay results showed that all three compounds (ErLR, EdLR, and ISL) increased osteoblastic-cell proliferation in a concentration-dependent manner for one day. In addition, both ErLR and EdLR compounds elevated the osteoblast proliferation for 5 or 20 days. Extracellular ALP activity was also increased as ErLR, EdLR, and ISL concentration increased at 20 days, which implies the positive effect of Glycyrrhiza species on osteoblast mineralization. The bone-related marker mRNAs were upregulated in the ErLR-treated osteoblastic MC3T3-E1 cells for 20 days. Bone-specific transcription factor Runx2 gene expression was also elevated in the ErLR- and EdLR-treated osteoblastic MC3T3-E1 cells for 20 days. Conclusion: These results demonstrated that Glycyrrhiza uralensis extracts may be useful for preventing osteoporosis by increasing cell proliferation, ALP activity, and bone-marker gene expression in osteoblastic cells.