https://www.selleckchem.com/CDK.html At least 40% of individuals with multiple sclerosis (MS) experience chronic insomnia. Cognitive behavioral therapy for insomnia (CBT-I) is an effective treatment for insomnia symptoms in individuals with MS. Delivery of CBT-I using Web-based applications has been shown to be effective and may increase access to CBT-I for individuals with MS who have mobility difficulties, experience fatigue, or live in rural areas. Therefore, the purpose of this study was to assess the feasibility and treatment effect of CBT-I delivered using a Web-based application with or without biweekly telephone calls to improve sleep quality and fatigue in individuals with MS and symptoms of insomnia. Forty-one individuals with MS and symptoms of insomnia were randomized into either a group that participated in a 6-week Web-based CBT-I program (wCBT-I) or a group that participated in a 6-week Web-based CBT-I program and received biweekly support telephone calls (wCBT-I + calls). Participants completed surveys online to assess insomnia severity, sleep quality, fatigue, sleep self-efficacy, depression, anxiety, and motivation to change their sleep behavior. The overall retention rate was 48.8%, and the adherence rate was 96.34%. Both groups had significant improvement in insomnia severity, sleep quality, sleep self-efficacy, and anxiety. Only the wCBT-I group had significant improvement in depression and fatigue. Web-delivered CBT-I is feasible and effective in improving sleep outcomes and concomitant symptoms in individuals with MS. Web-based CBT-I may increase access to CBT-I treatment and provide a stepped-care approach to treating chronic insomnia in individuals with MS. Web-delivered CBT-I is feasible and effective in improving sleep outcomes and concomitant symptoms in individuals with MS. Web-based CBT-I may increase access to CBT-I treatment and provide a stepped-care approach to treating chronic insomnia in individuals with MS. The current landscape