AbstractTissue engineering of bone has been increasingly used in the bone defect repair. To generate osteoblasts is a major approach, and here we have examined ways of improving the efficiency of producing osteoblasts. Adipose stem cells (ADSC) were prepared from rat mesentery tissue, and transfected with Cbfa1 gene vector or/and IGF‐1R gene vector. The cells were stimulated with insulin. Osteocalcin expression by the ADSCs was assessed by quantitative RT‐PCR (qRT‐PCR), Western blotting and enzyme‐linked immunobosorbent assay.Both genes Cbfa1 and IGF‐1R were transfected in ADSCs, as shown by qRT‐PCR and Western blotting. Stimulation by insulin in the culture increased osteocalcin expression in ADSCs transfected by both Cbfa1 and IGF‐1R, but not in those transfected with only one of these two genes. Osteocalcin in the culture supernatant was also increased by stimulation with insulin.Thus IGF‐1R gene transfer together with insulin stimulation can markedly increase the efficiency of generation of osteoblasts.