Background: More than one million people in Germany live with dementia. Most of these people are cared for at home in the family setting. Supporting and caring for people with dementia is time-consuming, and family carers often have high stress levels and are at an increased risk of becoming physically and mentally ill. Medical rehabilitation (rehab) helps to relieve family carers and provide them with strategies to cope with stress. The aim of this study is to improve the sustainability of a multimodal rehab program for family carers of people with dementia.; Research Question: can the effects of this rehab be maintained through telephone-based aftercare groups following the rehab program?; Methods: A prospective randomized controlled longitudinal trial is performed. The intervention group (IG) participates in telephone-based aftercare groups; the control group (CG) receives treatment as usual. For evaluation, a mixed-methods approach is used. The effects of the intervention are quantitatively evaluated by written questionnaires at four measuring points (pre- and post-rehab, as well as 6 and 12 months after the end of rehab).; Primary Outcome: participation (IMET).; Secondary Outcomes: Depressive Mood State CES-D, General Complaints SCL-90-R, Subjective Quality of Life WHOQUOL-BREF, Social Support F-SozU, performance in different areas of life, single scales, and support offers (single items). The intervention process is evaluated through qualitative interviews and focus groups with regard to the acceptance of and satisfaction with the aftercare offered; in addition, a health economic evaluation is performed using the EQ-5D questionnaire. Rehabilitants are included in the study (N = 103 each in the IG and CG) who, accompanied by their family members with dementia, participate in the rehab measure in Ratzeburg. The IG participates monthly in 6 telephone aftercare groups over a period of 6 months. Typical stress situations are discussed and worked on.; Discussion: Upon successful evaluation, the offer to participate in telephone-based aftercare groups can be firmly established in the participating rehab clinic. Through minor adjustments, the offer would also be suitable for carers of physically ill people and for non-nursing-specific rehabilitation indications.; Trial Registration: German Clinical Trials Register: DRKS00013736 , May 14, 2018.