Objectives: Homeless people lack a secure, stable place to live, and experience higher rates of serious illness than the housed population. Studies, mainly from the US, have reported increased use of unscheduled health care by homeless individuals. We compared the use of unscheduled ED and inpatient care between housed and homeless hospital patients in a high-income European setting. Setting: A large university teaching hospital serving the south inner city in Dublin, Ireland. Patient data is collected on an electronic patient record within the hospital. Participants: We carried out an observational cross-sectional study using data on all ED visits (n=47,174) and all unscheduled admissions under the general medical take (n=7,031) in 2015. Primary and Secondary Outcome Measures: The address field of the hospital’s electronic patient record was used to identify patients living in emergency accommodation or rough sleeping (hereafter referred to as homeless). Data on demographic details, length of stay and diagnoses was extracted. Results: In comparison to housed individuals in the hospital catchment area, homeless individuals had higher rates of ED attendance (0.16 attendances per person/annum vs 3.0 attendances per person/annum respectively) and inpatient bed days (0.3 bed days per person/annum vs 4.4 bed days per person/annum. The rate of leaving ED before assessment was higher in homeless individuals (40% of ED attendances vs 15% of ED attendances in housed individuals). The mean age of homeless medical inpatients was 44.19 (95% CI 42.98-45.40), whereas that of housed patients was 61.20 (95% CI 60.72-61.68). Homeless patients were more likely to terminate an inpatient admission against medical advice (15% of admissions vs 2% of admissions in homeless individuals). Conclusion: Homeless patients represent a significant proportion of ED attendees and medical inpatients. In contrast to housed patients, the bulk of usage of unscheduled care by homeless people occurs in individuals younger than 65.