Atelopeptide type I collagen derived from fresh porcine skin was evaluated as a carrier for ectopic osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2) in rats. Four treatment groups (N = 5) were examined: a control group in which only atelopeptide type I collagen was implanted, and groups II, III and IV in which atelopeptide type I collagen with 2, 10, 50 micrograms of rhBMP-2 was implanted in to the calf muscles of 10-week-old Wistar rats, respectively. Four weeks after the implantation, soft X-ray and light microscopic examinations were performed. In addition, calcium (Ca) content and alkaline phosphatase (ALP) activity were evaluated. New bone formation in the implanted regions (groups II, III and IV) were revealed. Bone formation was induced in the implanted region of even 2 micrograms of rhBMP-2 (group II), and its degree was dependent on the dose of rhBMP 2. These results indicate that atelopeptide type I collagen is an effective carrier for ectopic osteo-induction by rhBMP-2 and may act as a carrier for rhBMP in reconstructive surgery for bony defect and augmentation.