Objective: Work-related musculoskeletal disorders (MSDs) are the leading cause of work disability in the developed economies. The objective of this study was to describe trends in the incidence of MSDs attributed to work exposures in Ontario over the period 2004-2011. Methods: An observational study of work-related morbidity obtained from three independent sources for a complete population of approximately six million occupationally active adults aged 15-64 in the largest Canadian province. We implemented a conceptually concordant case definition for work-related non-traumatic MSDs in three population-based data sources: emergency department encounter records, lost-time workers compensation claims and representative samples of Ontario workers participating in consecutive waves of a national health interview survey. Results: Over the 8-year observation period, the annual per cent change (APC) in the incidence of work-related MSDs was -3.4 (95 CI -4.9 to -1.9 ) in emergency departments administrative records, -7.2 (-8.5 to -5.8 ) in lost-time workers compensation claims and -5.3 (-7.2 to -3.5 ) among participants in the national health interview survey. Corresponding APC measures for all other work-related conditions were -5.4 (-6.6 to -4.2 ), -6.0 (-6.7 to -5.3 ) and -5.3 (-7.8 to -2.8 ), respectively. Incidence rate declines were substantial in the economic recession following the 2008 global financial crisis. Conclusions: The three independent population-based data sources used in this study documented an important reduction in the incidence of work-related morbidity attributed to non-traumatic MSDs. The results of this study are consistent with an interpretation that the burden of non-traumatic MSDs arising from work exposures is declining among working-age adults.