Abstract Prolonged absences from work, especially those related to common mental disorders (CMD) and musculoskeletal disorders (MSD), impose considerable economic and human costs. Because of this, better understanding of the factors that hinder the return to work (RTW) of those affected by these two disorders is essential. According to the literature, it is well established that RTW is the result of a complex interaction between the individual and actors from various systems, such as the workplace and the healthcare and compensation systems. Apart from a few particularities or individual characteristics, including the symptoms inherent to a specific disorder or a variation in recovery time, in general, the obstacles perceived by people suffering from CMD or MSD during their RTW process overlap, to the extent that recent studies have begun to look at disabled workers as a single group, regardless of the nature of the disease or injury. The literature emphasizes the need to not only assess the obstacles perceived during RTW, but also to take into account the self-efficacy to overcome them, two essential and complementary concepts in assessing the factors involved in RTW. However, to our knowledge there is no tool adapted to those dealing with CMD or MSD in the literature that measures both the obstacles related to RTW and the self-efficacy to overcome them. The objective of this prospective study is to validate a tool entitled Return-to-work Obstacles and Self Efficacy Scale (ROSES) with employees in the RTW process as a result of CMD or MSD. Specifically, it will validate the psychometric properties related to ROSES: (1) content validity (2) face validity, (3) construct validity, (4) test-retest reliability, and (5) predictive validity. This study consisted of three phases. In phase 1, participants who met the inclusion criteria and who consented to participate in the study completed the ROSES questionnaire (CMD (n=157) or MSD (n=206)) and a sociodemographic questionnaire. Phase 2 took place two weeks later, to respond to the demands of the test-retest reliability assessment. Finally, phase 3, which took place six months after phase 1, enabled the predictive validity of ROSES to be assessed using regression analyses. All the participants in phase 1 were then re-contacted by telephone to learn whether or not they had returned to their occupational activity. Content and face validity. The initial version of ROSES had 97 statements divided into six broad conceptual categories. Construct validity. In terms of factor analyses (exploratory and confirmatory) and internal reliability analyses performed for the conceptual categories that had been previously constructed, a total of 46 statements divided among 10 dimensions emerged: (1) fears of a relapse, (2) cognitive difficulties, (3) medication-related difficulties, (4) job demands, (5) feeling of organizational injustice, (6) difficult relation with immediate supervisor, (7) difficult relation with co-workers, (8) difficult relations with the insurance company, (9) difficult work/life balance, (10) loss of motivation to return to work. Reliability. The results of the correlation analyses showed that these 10 dimensions remain stable over time (2 weeks) in the two groups (CMD and MSD). Predictive validity. In addition to the number of weeks of absence from work and the perceived pain, four dimensions (perceived obstacles and self-efficacy) are predictive of RTW in people with MSD: fears of a relapse, job demands, the feeling of organizational injustice, and a difficult relationship with the immediate supervisor. Among people with a CMD, only the job demands and cognitive difficulties stood out as being significant. To conclude, the study made it possible to validate ROSES. This tool fills a theoretical gap in the literature by showing that biopsychosocial obstacles and the self-efficacy to overcome them should be taken into account in predicting the RTW of people with CMD or MSD. Clinically, the study provides rehabilitation health professionals with a valid tool and simple administration (46 statements covering 10 dimensions), which makes it possible for them to systematically assess these two concepts among their clients. They can thus optimize their activities to facilitate their clients’ RTW. ROSES is a working and dialogue tool for the two interlocutors. Once the identification of dimensions or problematic statement pairs has been settled, rehabilitation professionals can begin a discussion with their clients and establish the relevant activities and strategies. In addition, rehabilitation health professionals may decide to use ROSES as a follow-up tool in order to evaluate whether certain obstacles have disappeared or if they persist in their clients’ workplaces or personal lives.