A comparative study was undertaken in rabbit tibiae to assess the healing of bone in response to osteotomies by a XeCl 308-nm excimer laser and a mechanical saw. The laser parameter producing the most efficient ablation rate for osteotomy was determined and shown to produce deep cuts with sharp edges. However, it was noted histologically that there was a significant delay in healing of the laser osteotomies compared with saw osteotomies. This delay was caused by thermal damage to bone adjacent to the laser cuts. It is suggested that the excimer laser at this wavelength ablates bone primarily through a photothermal as opposed to a photodissociative mechanism.