The study of both DNA and protein technologies has been marked by unprecedented achievement over the last decade. The completion of the Human Genome Project in 2003 is representative of a new era in genomics; likewise, proteomics research, which has revolutionized the way we study disease, offers the potential to unlock many of the pathophysiologic mechanisms underlying the clinical problems encountered by orthopaedic surgeons. These new fields are extending our approach to and investigation of the etiology and progression of musculoskeletal disorders, notably rheumatoid arthritis and osteoarthritis. Advances in proteomics technology may lead to the development of biomarkers for both rheumatoid arthritis and osteoarthritis. Such biomarkers would improve early detection of these diseases, measure response to treatment, and expand knowledge of disease pathogenesis.