Fibrin is a natural polymer with excellent biocompatibility and widely used as a cell delivery vehicle in tissue engineering. However, fibrin of low concentration is not able to promote cell growth and differentiation within a desired time because of contraction and biodegradation of cell-seeded matrices. In this study we investigated effects of combining fibrin with collagen on growth and osteogenic differentiation of bone marrow stromal cells (BMSCs). Rabbit BMSCs-populated fibrin hydrogels with or without collagen were fabricated and cultured by the free floating method for 4 weeks. The DNA content of fibrin/collagen matrix significantly increased the growth of BMSCs compared to the fibrin-only matrix at 2week. Alkaline phosphatase activity was significantly higher in the fibrin/collagen matrix (71.0 nmol of p-nitrophenol /min/disc) than the fibrin-only matrix (45.1 nmol of p-nitrophenol /min/disc). Deposition of calcium was not significantly different between two groups. Histological examination also revealed more matured organization and deposition of collagen fibers and more concentric calcium deposition in the fibrin/collagen matrix compared to the fibrin-only matrix. These results indicated that fibrin/collagen matrix could be more effective than fibrin alone in supporting growth and osteogenic differentiation of BMSCs.