Introduction - The objective of this study is to compare two InVS surveillance programs, MCP (Occupational Diseases) and Samotrace, in the field of occupational mental health. Methods - Both programs rely on a network of occupational physicians. The comparison is based on data collected in the Centre region and neighboring areas between 2006 and 2008 for Samotrace and in 2008 for MCP. In MCP, work-related mental distress was diagnosed by the occupational physician. In Samotrace, mental distress was assessed using the GHQ-28 self-report questionnaire, and the proportion attributable to work was calculated based on program data. Results—The prevalence of work-related mental distress in both programs ranged from 1% to 5%. Among men, both programs agree that the highest prevalence rates are found among intermediate-level occupations and clerical workers. Among women, however, an upward gradient from blue-collar workers to managers was observed in MCP, while an inverse gradient—albeit not statistically significant—was observed in Samotrace. Discussion - This study, which aimed to compare two approaches to estimating the prevalence of work-related mental distress, shows a fairly good agreement between the results but also some discrepancies. It demonstrates the need for further research in this area and the value of having multiple data sources. (R.A.)