Acute inpatient falls are common and serious adverse events that lead to injury, prolonged hospitalization and increased cost of care. To determine the difference in total acute hospital care length of stay (LOS) for patients with and without an in-hospital fall (IHF), regardless of degree of harm. This was a retrospective observational study at a 728-bed acute care teaching hospital. We used propensity scores to match 292 patients with 330 controls by case mix group, sex, Resource Intensity Weights and week of admission. We used two administrative databases: hospital fall incident reporting system and Discharge Abstract Database. We reviewed all IHF incidents for patients 18 years and older, admitted to inpatient acute care hospital units/programs between 1 November 2009 and 31 August 2011. The average LOS for IHF cases was 37.2 days [median 26.5 days; interquartile range (IQR) 14, 54] and 25.7 days (median 13 days; IQR 5, 33) for matched control patients. Survival analysis results indicated that patients who did not have an IHF were 2.4 times (95% CI 2.1, 2.7; P < 0.001) more likely to be discharged earlier from acute care than patients who had an IHF. Experiencing either an injurious or a non-injurious fall during an acute care hospitalization was associated with prolonged LOS.