Introduction. Carotid-cavernous arteriovenous fistula is an abnormal connection between the internal or external carotid arteries and the brain venous system within the cavernous sinus. Post-traumatic aetiology is most frequent; spontaneous fistulas are rare. The main clinical symptom is pulsating exophthalmia; other symptoms depend on the localization and haemodynamic features of the fistula. Frequently, palsies of the IIIrd, VIth and VIIth cranial nerves dominate in the clinical picture, contributing to diagnostic problems. Aim. To present a case study of a post-traumatic patient with a head injury and with atypical symptoms of carotid-cavernous arteriovenous fistula. Discussion. A 22-years old patient was admitted to the Department of Neurology with a periorbital ecchymosis and symptoms of the unilateral palsy of the IIIrd and the VIth nerves, after a head injury which had taken place a few days before. The symptoms of carotid-cavernous arteriovenous fistula appeared late and the clinical picture was dominated by damage to the cranial nerves. Initially, these symptoms were treated as complications of the skull fracture. A slightly intensified pulsating exophthalmia was observed. A gradual asymmetric swelling of the eyeballs, a lack of improvement following the treatment of the damaged cranial nerves as well as ophthalmologic consultations necessitated further diagnostic examinations. MRI and angio-MRI of the brain were performed, revealing a left carotid-cavernous arteriovenous fistula. The patient was transferred to an endovascular centre to undergo the embolisation of the fistula. Conclusions. Carotid-cavernous arteriovenous fistula may manifest itself after several days following a head injury. Occasionally, the intensity of the pulsating exophthalmia is relatively small and the symptoms of damage to the cranial nerves predominate. Early diagnosis, even of atypical forms of carotid-cavernous arteriovenous fistula, may prevent irreversible blindness or considerable loss of sight.