A method for purifying bone-derived osteoinductive proteins including a demineralization process, a protein extraction process, a high molecular weight ultrafiltration process, a low molecular weight ultrafiltration process, and a recovery process. The high and low ultrafiltration processes preferably select proteins having a nominal molecular weight between approximately 8 kilodaltons and approximately 100 kilodaltons. Processes of the present invention may be used to recover osteoinductive proteins from bone demineralization waste streams.