BACKGROUND Circular RNAs (circRNAs) play important roles in gene expression and signaling pathways. The study aimed to identify the differential expression of circRNAs and mRNAs in the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and to explore the biological function of circRNAs in the osteogenic differentiation of rBMSCs. MATERIAL AND METHODS High-throughput sequencing was used to detect differentially expressed circular RNA and mRNA during osteogenic differentiation of rBMSCs. The RNAs were analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment to predict their potential role in regulating rBMSC osteogenesis. MiRanda, Circatlas, and miRDB databases were used to predict target relationships between circRNA, miRNA, and mRNA.The regulatory network was constructed by Cytoscape (version 3.6.1). The RNA-Seq findings were validated by quantitative real-time PCR (qRT-PCR). RESULTS The results revealed that 29 differentially expressed circRNAs and 2453 differentially expressed mRNAs were detected during the osteogenic differentiation of rBMSCs. Many differentially expressed circRNAs were closely related to osteogenic differentiation of cells. Among them, circRNAs_1809 and Kitlg were the significantly increased circRNA and mRNA during osteogenic differentiation of rBMSCs. The ceRNA network showed that circRNA_1809 could target the Kitlg gene through miR-370-3p. CONCLUSIONS CircRNAs may play an important role in the osteogenic differentiation of rBMSCs. CircRNA_1809 may acts as a sponge for miR-370-3p and regulate the osteogenic differentiation of rBMSCs by targeting Kitlg; however, this hypothesis needs further verification. This study laid a theoretical foundation for further understanding the mechanism of circRNAs regulating osteogenic differentiation of rBMSCs.