IntroductionOlder people in need of home care are at risk of declining oral health as their visits to dentists are becoming less frequent due to restricted mobility. There is increasing evidence that poor oral health and systemic diseases are closely associated, for example, in cardiological, metabolic or neurodegenerative conditions. Thus, Interaction of Systemic Morbidity and Oral Health in Ambulatory Patients in Need of Home Care (InSEMaP) is investigating the need, provision and utilisation of oral healthcare, systemic morbidity and clinical status of the oral cavity in older people.Methods and analysisInSEMaP consists of four subprojects (SP), all involving the target population of older people in need of home care. In SP1 part a, a sample is surveyed using a self-report questionnaire. In SP1 part b, stakeholders (general practitioners, dentists, medical assistants, family and professional caregivers) are interviewed regarding barriers and facilitators using focus groups and personal interviews. In SP2, a retrospective cohort study, health insurance claims data are examined to investigate the utilisation of oral healthcare, its association with systemic morbidity and healthcare costs. In SP3, a clinical observational study will assess the oral health of participants by a dentist’s visit at home. SP4 synthesises the results of SP1, SP2 and SP3 to develop integrated clinical pathways, identifying strategies to uphold oral healthcare in older people. In assessing and evaluating the process of oral healthcare, and its associated systemic morbidity, InSEMaP aims to improve general healthcare across the sector boundary of dental and general practitioner care.Ethics and disseminationEthics approval was obtained from the Institutional Review Board of the Hamburg Medical Chamber (approval number: 2021-100715-BO-ff). The results of this study will be disseminated through conference presentations and publications in peer-reviewed journals. An expert advisory board to support the InSEMaP study group will be established.Trial registration numberGerman Clinical Trials Register: DRKS00027020.