Falls represent 40 per cent of hospital accidents, and consequences range from none to serious injuries. The purpose of this study was to estimate the average hospital cost and length of stay (LOS) associated with serious injurious falls in an acute care hospital. We used data from risk management and case costing databases to identify cost associated with a serious injury after an in-hospital fall. Thirty-seven injured patients were matched with 2,113 controls by the most responsible medical diagnosis, age, and gender. Cost and LOS were compared using t-tests and multivariate regression. Average costs for seriously injured fallers and non-faller controls were CAD$44,203 and CAD$13,507, while LOS was 45 and 11 days respectively. Hospital cost for a seriously injured faller was $30,696 (95% CI: $25,158 - $36,781) greater than the cost for a non-faller. Hospital managers have a leading role in creating system-wide falls prevention programs and reducing hospital costs.