OBJECTIVE: A model adjusting for reductions in quality and quantity of life was developed to estimate the population health impact of musculoskeletal diseases. METHODS: Using arthritis as the prototype, prevalence, mortality, and severity data from a variety of sources were combined to model a hypothetical cohort of 1,000 individuals through life. Quality adjusted life years and population health expectancy were calculated for those with arthritis and compared to the general population. RESULTS: Without adjusting for quality of life, a cohort of 1,000 women and 1,000 men at age 15 years could expect 65,010 and 58,735 life years, respectively. Adjusting for quality of life, women with arthritis could expect 61,719 life years, and men 57,123 life years. The unadjusted population health expectancy was 65.0 for girls and 58.7 for boys (at age 15 years). Adjusting for quality of life, the population health expectancies were 61.7 and 57.1, years for women and men, respectively. CONCLUSION: Using this model, the typical adult woman with arthritis can expect to lose 3.3 healthy years of life, and a man, 1.6 healthy years of life. Overall, the model provided a general methodology for determining the population health impact of musculoskeletal diseases. In addition, it is hoped that the methodology will stimulate further research into this area, raise awareness about the uses and limitations of currently available data, and provide a useful model for monitoring the impact of interventions.