Homelessness is associated with high risks of morbidity and premature death. Many interventions aimed to improve physical and mental health exist, but do not reach the population of persons experiencing homelessness. Despite the widely reported unmet healthcare needs, more information about the barriers and facilitators that affect access to care for persons experiencing homelessness is needed. A systematic integrative review was performed to explore experiences and needs of health- and social care for persons experiencing homelessness. The following databases were searched: AMED, ASSIA, Academic Search Complete, CINAHL, Cochrane library, Nursing and Allied Database, PsycInfo, PubMed, Scopus and Web of Science Core Collection. Twenty-two studies met the inclusion criteria of empirical studies with adult persons experiencing homelessness, English language, and published 2008-2018. Fifty percent of the studies were of qualitative and quantitative design, respectively. Most studies (73%) were conducted in the United States (n=11) and Canada (n=5). The analysis resulted in three themes Unmet basic human needs, Interpersonal dimensions of access to care, and Structural and organizational aspects to meet needs. The findings highlight that persons in homelessness often must prioritize provision for basic human needs, such as finding shelter and food, over getting health- and social care. Bureaucracy and rigid opening hours, as well as discrimination and stigma, hinder these persons' access to health- and social care.