Background: underreporting of occupational diseases (OD) has been quantified, in particular in the United States, but little information is available in other countries. The aim of this study was to evaluate underreporting of musculoskeletal disorders (MSD) in France in 2009. Methods: we calculated an indicator that approximated the underreporting rate of MSD in 10 regions of France. Two databases were used: data on OD compensated by insurance funding and data from the surveillance program for uncompensated work-related diseases. Analyses were performed for carpal tunnel syndrome (CTS) and elbow, shoulder, and lumbar spine MSD. Methods: the underreporting rate was estimated at 59% (range 52-64%) for CTS, 73% (range 67-79%) for elbow MSD, 69% (range 63-74%) for shoulder MSD, and 63% (range 50-76%) for lumbar spine MSD. Conclusions: this study revealed that MSD are substantially underreported in France, as in the United States, despite the differences in workers" compensation systems. Am. J. Ind. Med. 57:1174-1180, 2014. © 2014 Wiley Periodicals, Inc. (R.A.)