Aims:Various types of musculoskeletal disorders (MSDs) have comorbid mental disorders, which may in turn have a negative influence on disease course and role impairment, but the contribution of social factors to this type of comorbidity is a much under-researched area. This study investigates whether there is a socially patterned association of MSDs with different dimensions of mental malaise. Methods: The sample included 3,368 economically active participants aged 18—64 years, randomly selected from the Lorraine region in north-eastern France. Information was provided through a post-mailed questionnaire on fatigue, sadness/depression (Duke questionnaire) and cognitive disability during the last eight days. Results: MSDs were significantly more prevalent in manual workers, clerks and other occupations than in upper and intermediate professionals, and similar occupational disparities were found for cognitive disability, fatigue and sadness/ depression. Stratifying the sample, we found the occupational disparities in cognitive disability to be much stronger among participants suffering from MSDs than among participants not suffering from MSDs, and the occupational disparities in fatigue and sadness/depression to be limited to the subsample of subjects suffering from MSDs. Conclusions: The findings demonstrate that the association of MSDs with mental malaise is much stronger in the lower occupational groups than in the higher groups. Given that psychological factors are implicated in disease prognosis and in the development of disabilities, awareness of the social dimension of the association and treatment of the comorbid mental disorders could open a promising avenue for reducing social inequalities in disability related to MSDs.