Background: People with intellectual disabilities may have inequalities in hospital admissions compared with the general population. The present authors aimed to investigate admissions for physical health conditions in this population. Methods: The present authors conducted a systematic review, searching six databases using terms on intellectual disabilities and hospital admission. Papers were selected based on pre-defined inclusion/exclusion criteria, data extracted, tabulated and synthesized and quality assessed. PROSPERO registration number: CRD42015020575. Results: Seven of 29,613 papers were included. There were more admissions, and a different pattern of admissions (more medical and dental), for people with intellectual disabilities, but most studies did not take account of higher disease prevalence. Three papers considered admissions for ambulatory care-sensitive conditions, two of which accounted for disease prevalence (asthma, diabetes) and found higher admission rates for people with intellectual disabilities. Conclusion: Admissions are common. Asthma and diabetes admission data suggest suboptimal primary health care for people with intellectual disabilities compared with the general population, but evidence is limited.