Open tibial fractures have a high infection risk making treatment difficult and expensive. Delayed skin closure (beyond 7 days) has been shown to increase the infection rate in several studies (1). We aim to calculate the cost of infection as a complication of open tibial fractures and to determine the effect of delayed skin closure on this cost. We retrospectively reviewed all records of patients treated with a free flap in our institution for an open tibial fracture from 2002 to 2013. We calculated direct costs of treatment by the DRG-values (2014 figures), based on length of stay (LOS), diagnosis, orthopaedic and plastic surgical procedures and the corresponding reimbursement. The primary goal was to establish the extra cost incurred by an infection, compared to treating an uninfected open tibial fracture. The cost efficiency saving of early soft tissue cover was also investigated. We analysed 45 injuries in 44 patients. All patients were treated with debridement, stabilization, prophylactic antibiotics and free flap cover. Infection increased the mean total LOS in hospital from 28.0 to 63.8 days. The presence of an infection increased the cost of treatment from a mean of €49.301 for uninfected fractures compared to a mean of €67.958 for infected fractures. Achieving skin cover within 7 days of injury decreased the infection rate from 60% to 27% (total series rate 48%). The provision of early soft tissue cover (before 7 days) for all patients would have saved an average of €18.658 per patient. The development of an infection after a severe open tibial fracture greatly increases the cost of treatment. Early soft tissue cover is one aspect of care which has been shown to improve clinical outcomes. This study confirms that it will also reduce the cost of treating these complex fractures – underscoring the need for rapid referral and an ortho-plastic setup to handle them. We have only calculated the direct costs of treatment. Infected fractures will also consume extra costs in rehabilitation and absenteeism from later infection recurrence and non-union. Therefore, our estimate of the potential saving is likely to be conservative.