The authors studied computed tomographic (CT) scans obtained in 40 patients with transsphenoid basilar skull fractures to establish if there were reproducible patterns of fracture along lines of weakness. Medical records were reviewed. Four major fracture patterns were identified: anterior transverse (n = 22), lateral frontal diagonal (n = 7), posterior transverse (n = 16), and mastoid diagonal (n = 3). Eight patients had two fracture patterns. Eleven of 40 patients (28%) died as a result of their head injury. The diagonal patterns were statistically significantly more frequently associated with in-hospital mortality than were the transverse fractures (P = .014). Complications included blindness, cranial nerve injury, cerebrospinal fluid leak, and hearing loss. These results indicate that transsphenoid basilar skull fractures occur along reproducible lines of weakness, including a coronal plane through the anterior sphenoid body and pterygoid plates, a coronal plane through the posterior sphenoid body and clivus, and the sphenopetrosal synchondrosis.