Unwanted dural injury in spinal surgery has been reported at varying rates and is seen extremely often. Death as a consequence of subdural hematoma following incidental dural injury is a very rare complication. The purpose of this study is to present a case of fatal subdural hematoma as a complication of dural injury which was not noticed during surgery. Here, we present a 40-year old female with congenital kyphosis of approximately 100 degrees at the T9-L2 level who underwent corrective spinal surgery in the form of laminectomy, foraminectomy, and partial corpectomy. The patient experienced a rapid deterioration in her level of consciousness and died within 3 days. We conclude that incidental dural injury which has not been noticed during the operation with subsequent subdural hematoma can be a fatal complication related to CSF leakage.