Caregivers of persons with multiple sclerosis (MS) engage in many caregiving tasks and spend considerable time on these activities with such caregiving being of immense social and economic value. However, the lack of empirically derived psychometrically sound instruments for measuring caregiving tasks has hampered progress in this field. This study aimed 1) to examine the dimensional and psychometric structure of the Caregiving Tasks in MS Scale (CTiMSS), and 2) to examine caregiver and care recipient correlates of caregiving tasks. Participants were 232 caregivers of persons with MS and their care recipients. Questionnaires were completed at Time 1 and 12 months later (Time 2). Factor analyses showed that the CTiMSS could be represented by a single dimension or four caregiving domains: Instrumental Care, Activities of Daily Living Care, Psycho-emotional Care, Social-practical Care. The CTiMSS factors were psychometrically sound and evidenced differential relations with most caregiver and care recipient characteristics and predicted changes in adjustment over 12 months. Findings delineate the key dimensions of MS caregiving and show the differential links between caregiving task domains and caregiver and care recipient characteristics. Results provide preliminary reliability and validity data on the first published measure of caregiving tasks in MS. Such an instrument is important for theory building, across study comparisons and the development of services.