Hospital length of stay (LOS) is frequently used to evaluate the quality of trauma care but LOS may be impacted by nonmedical factors as well. We reviewed our experience with delays in patient discharge to determine its financial consequences and its impact on LOS. We performed an analysis of linked trauma registry and "delayed discharge" databases. Actual LOS (A-LOS) values were compared with calculated ideal LOS (I-LOS) values, and the per cent increase in LOS was calculated. Linear regression analysis was used to identify significant predictors of prolonged LOS. One thousand, five hundred and seventeen patients were studied, with an A-LOS of 6.54 days. Seven per cent of patients experienced discharge delays, resulting in 580 excess hospital days. Calculated I-LOS was 6.15 days, 6.34 per cent lower than A-LOS. Other I-LOS estimates were as much as 25 per cent lower than A-LOS. Estimated excess patient charges associated with delayed discharges were $4,000,000 to $15,000,000. Discharge delays are an infrequent, although costly, occurrence that has a significant impact on LOS. LOS therefore may not be an appropriate metric for assessing the quality of trauma care, and should only be used if it has been corrected for discharge delays. Concerted efforts should be directed towards identifying and correcting the factors responsible for delayed discharge in trauma patients.