The objective of this study was to assess the bone formation ability of a DBM-BMP-2 complex for the treatment of bone defect of the ulna in pigs. After 2-cm bony defects were made in the diaphysis of both ulnas in 12 pigs, DBM or DBM-BMP-2 complex was grafted to the bony defect using the experimental protocol. As a control, the bone defect on one side was left untreated. New bone formation of the bony evaluated by taking simple radiographs on the day of surgery, and on the 4th, 8th, 12th and 16th week thereafter. On the 16th week, a three dimensional CT scan was obtained to analyze the volume of new bone formation. A biomechanical study was performed to compare the strength of the bone union site and the histologic findings were evaluated. There was no significant difference between the control and DBM group on the simple radiographs. However, the DBM-BMP-2 complex showed significant improvement in bone formation. According to the biomechanical test and the volume of new bone formation assessed using the three dimensional CT scan, there was no significant difference between the control and DBM group, whereas there was significant improvement in the DBM-BMP-2 complex group. The histologic findings were similar in all three groups. The DBM-BMP-2 complex produced a better outcome in the treatment of bone defects of the ulna in pigs than the DBM graft alone.