BackgroundImplementing dementia care interventions in an acute hospital poses multiple challenges. To understand factors influencing the implementation, in-depth knowledge about specific facilitators and barriers is necessary. The aim of this study was to identify facilitators and barriers to implementing an interprofessional, multicomponent intervention of a specialized unit for persons with cognitive impairment in an acute geriatric hospital.MethodsWe conducted a process evaluation as part of a participatory action research study. For data collection, semi-structured individual interviews with fifteen professionals involved in the implementation of the specialized unit. We further conducted two focus groups with twelve professionals working on other units of the geriatric hospital. We performed a qualitative content analysis following Kuckartz’s content-structuring analysis scheme.ResultsWe identified the following barriers to implementing the specialized unit: uncontrollable contextual changes (e.g., COVID-19 pandemic), staff turnover in key functions, high fluctuation in the nursing team, traditional work culture, entrenched structures, inflexible and efficiency-oriented processes, monoprofessional attitude, neglect of project-related communication, and fragmentation of interprofessional cooperation. An established culture of interprofessionalism, an interprofessionally composed project group, cooperation with a research partner, as well as the project groups’ motivation and competence of managing change facilitated the implementation.ConclusionsThe implementation faced numerous barriers that can be described using the key constructs of the i-PARIHS framework: context, recipients, innovation, and facilitation. Overcoming these barriers requires an organizational development approach, extended project duration and increased process orientation. Furthermore, strategically planned, precise and ongoing communication towards all persons involved seems crucial. Differences between the work cultures of the professions involved deserve particular attention with regard to project-related roles and processes.