Aims and objective To explore the experience of adult patients and adult patients’ families, and their perception of the support systems received during the diagnostic process of rare diseases. Background There are about 7,000 rare diseases that affect 7% of the world's population. Rare diseases are often underdiagnosed. This has been reported to have deleterious physical and psychological consequences in both the patients and their families, especially when institutional support during this process is low. Design A scoping review was carried out following the 6-phase model proposed by Arksey & O’Malley and Levac et al., including the consultation phase in which patients diagnosed with rare diseases were interviewed to seek their views on the bibliographic evidence reviewed and their experience during the diagnostic process. Methods The databases consulted were PubMed, CINAHL, Web of Science, SCOPUS, Cochrane Library, PsycINFO, OpenGrey, ProQuest Dissertations and Theses Global. They were explored from inception–July 2020, and qualitative, quantitative and mixed method studies were included. The Mixed Methods Appraisal Tool was used for the critical evaluation of the articles. The review was based on the guidance in the PRISMA-ScR statement. Results The initial search identified 2,350 articles, of which 20 fully met the inclusion criteria and were therefore reviewed. In this analysis appeared two dimensions: internal factors: emotional aspects, and external factors: resources and support systems. Relevance to clinical This review provides evidence on the emotional impact of the diagnostic process and during the communication phase of the definitive diagnosis. Health systems and professionals must be strengthened in order to improve the information, training and resources. Nurses can play a key role in coordinating communication and follow-up of those affected.