Creating a solid lumbar spinal fusion remains a challenge. Despite advances in fixation, a pseudarthrosis still may occur. Recently, attention has focused on creating a more biologically favorable environment to enhance fusion rate. Bone morphogenetic proteins (BMPs) are a group of secreted growth factors that belong to the transforming growth factor-beta superfamily. Two recombinant BMP proteins, rhBMP-2 and rhBMP-7 (OP-1), have been used successfully in preclinical and clinical trials and are commercially available for clinical applications.