The goal of this study was to assess the potential of fermented Cudrania tricuspidata leaf (CTL) aqueous extract as a functional food material. The CTL aqueous extract was fermented using lactic acid bacteria (LAB) isolated from soybean-fermented foods and the biological effects of the resultant fermented extracts on MG-63 human osteoblastic cells and 3T3-L1 mouse pre adipocytes were examined in vitro. We found that (1) the radical scavenging activities of CTL extracts fermented by various LAB strains (fermented CTL, F-CTL) were ~2- fold higher than that of non-fermented CTL extract (NFCTL), (2) F-CTL extract enhanced MG-63 cell proliferation compared to NF-CTL-treated cells, (3) the level of alkaline phosphatase activity in F-CTL-treated MG-63 cells was significantly higher than that in NF-CTL-treated cells, and (4) 3T3-L1 cell differentiation was dramatically decreased by F-CTL treatment, but not by NF-CTL. These findings suggest that CTL that has undergone LAB-mediated fermentation may be beneficial for promoting osteogenic differentiation of osteoblastic cells and inhibiting fat accumulation in adipocytes.