The objective of this systematic review was to summarize the best available evidence on the factors that increase the risk of patients falling during hospitalization. Studies included in the review were those that involved adult patients in hospital, that attempted to identify risk factors for falling, and used a cohort or case-control research design. The search strategy covered all major databases and including MEDLINE, CINAHL, Current Contents, Psyclit, Embase and the Cochrane Library. Results were summarized by a narrative discussion, identifying risk factors that were commonly identified in a range of practice settings. Eighteen papers met the review inclusion criteria and are reported in this paper. Factors associated with an increased risk of falling include impaired mental status, special toileting needs, impaired mobility, and a history of falling. While findings are contradictory, it appears that both medications and advanced age will also influence a patient's risk of falling.