[en] The purpose of this paper is to present the construction and validation of a questionnaire in order to evaluate the specific work difficulties and compensation mechanisms developed by multiple sclerosis patients (MS). At the moment, only few very recent questionnaires (in English) are constructed in order to highlight the link between the patients’ cognitive deficits with their professional situation (Doogan & Playford, 2014; Honan et al., 2012; McFadden et al., 2012). This lack of accurate assessment is detrimental to the patients’ job retention. Our questionnaire was constructed from review of literature and interviews of patients and experts. In order to validate our questionnaire and to test its specificity to MS patients, three groups of participants answered the questionnaire: MS patients, diabetic patients (diabetes is also a chronic illness but without any cognitive deficits contrary to MS) and a control group. We controlled the effect of anxiety and depression and we conducted a factorial analysis that showed the existence of 3 factors: the ergonomic factor (that includes cognitive difficulties and resources and adaptation process), the description of work situation and the social support. The three groups of participants obtained similar results for the work description and the social support while the group of patients with MS obtained a higher score than the other 2 groups for the ergonomic factor. These results suggest that our questionnaire is specific to the MS population and to the difficulties they specifically meet in their work situations. These results highlight new research opportunities and specific ways to increase job retention in MS population.