Falls are among the most common unwanted events in older hospital inpatients, but evidence of effective prevention is still limited compared with that in the community and in long-term care facilities. This article describes a prevention program and its effects on the incidence of falls in geriatric hospital wards. It was a prospective cohort study with historical control including all 4,272 patients (mean age 80, 69% female) before and 2,982 (mean age 81, 69% female) after introduction of the intervention. The intervention included fall-risk assessment on admission and reassessment after a fall; risk alert; additional supervision and assistance with the patients' transfer and use of the toilet; provision of an information leaflet; individual patient and caregiver counseling; encouragement of appropriate use of eyeglasses, hearing aids, footwear, and mobility devices; and staff education. Measurements included standardized fall-incidence reporting, activity of daily living and mobility status, number of falls and injurious falls, and number of patients who fell. Before the intervention was introduced, 893 falls were recorded. After the intervention was implemented, only 468 falls were recorded (incidence rate ratio (IRR)=0.82, 95% confidence interval (CI)=0.73–0.92), 240 versus 129 total injurious falls (IRR=0.84, 95% CI=0.67–1.04), 10 versus nine falls with fracture (IRR=1.40, 95% CI=0.51–3.85) and 611 versus 330 fallers. The relative risk of falling was significantly reduced (0.77, 95% CI=0.68–0.88). A structured multifactorial intervention reduced the incidence of falls, but not injurious falls, in a hospital ward setting with existing geriatric multidisciplinary care. Improvement of functional competence and mobility may be relevant to fall prevention in older hospital inpatients.