A clinically relevant number of fractures have impaired or delayed healing. New treatment methods that advance bone healing are, therefore, clinically desirable. In addition, it would be very helpful if these treatment methods could be used in conjunction with established methods. The aim of this study was to evaluate the influence of a single application of rhBMP-2 in the osteotomy line on bone healing in a sheep mandible osteotomy model. An osteotomy cut (width 0.5 mm) was made in the mandible, between the first molar and the mandibular nerve, using a standardised surgical procedure. After osteosynthesis, rhBMP-2 (280 µg in hyaluronic acid) was applied in the osteotomy line. The other sheep mandible site served as control. The animals were sacrificed after 4 and 8 weeks. Bone formation was measured using histomorphometric analysis and 3D-CT scans. Macroscopically, a larger callus formed after 4 and 8 weeks at the untreated mandible study site. 3D-CT scan measurements revealed that rhBMP-2 application led to a significantly lower callus volume after 4 and 8 weeks (p = 0.038). In the morphometric analysis, more than 40% of the untreated osteotomy lines were ossified after 4 weeks. When rhBMP-2 had been applied, 67.9% of the osteotomy line areas were ossified. In comparison to the untreated site, this difference was significant (p = 0.024). After 8 weeks, the ossified area of the test site had increased in comparison to the untreated site, and the difference was still significant (p = 0.021). Application of rhBMP-2 into the osteotomy line had a significant influence on bone healing. Therefore, clinical application of rhBMP-2 might be useful for fractures that are not entirely reducible or for defect fractures. In these cases, rhBMP-2 might correct the defect and lead to an earlier stability. Schlagwörter: rhBMP-2, Knochenheilung, Histomorphometrie