Introduction: Underreporting of work-related conditions—defined as conditions that do not enter the workers’ compensation system even though they meet the criteria—has been quantified for musculoskeletal disorders (MSDs) since 2007. The objective of this study was to update the underreporting indicator for 2011 for four types of MSDs (shoulder, elbow, lumbar spine, and carpal tunnel syndrome). Materials and methods: The indicator was calculated based on the number of MSDs recognized as occupational diseases (under the general social security system and the agricultural system) and the number of unrecognized MSDs, estimated using the Occupational Disease Surveillance Program (MCP) in 11 French regions in 2011. It was analyzed by sex and age. The reasons for non-reporting collected in the MCP program were described according to the location of the MSD and the type of employment contract. Results: The underreporting indicator ranged from 53% (range: 37–66%) for the lumbar spine to 73% (68–79%) for the elbow. Refusal to report (more common among employees on temporary contracts than among those on permanent contracts), insufficient diagnostic information, or lack of knowledge of the procedure were each cited by about one-third of respondents as reasons for non-reporting. Discussion - Conclusion: The update of the indicator for 2011 confirms the extent of underreporting of MSDs, which has remained stable for carpal tunnel syndrome and elbow MSDs but appears to have decreased for the lumbar spine and shoulder since 2007, reflecting a probable improvement in reporting.