Carotid-cavernous sinus fistula (CCF) is a syndrome in which arteriovenous shunts exist between the carotid artery and the cavernous sinus. These shunts vary widely in pathogenesis, angiogram, haemodynamics and treatment. Several systems of classification in terms of either haemodynamics, aetiology and/or pathogenesis have been reported, but they are not comprehensive. A more comprehensive and simpler nomenclature of classification is now required. Fifty seven cases of CCFs were analyzed and were classified according to their pathogenesis, angiography and treatment modalities. There were 11 traumatic CCFs with direct shunts (T-D group), and 2 traumatic CCFs with indirect shunts (T-I group). Spontaneous CCFs were divided into three groups. There were 37 spontaneous CCFs caused by dural arteriovenous shunts that were naturally classified as being indirect shunts (SD-I group). There were 5 spontaneous CCFs caused by suspected connective tissue disorders, such as fibromuscular dysplasia, Ehlers-Danlos syndrome etc.; these had direct shunts. Care was needed to avoid dissection of the artery or complications due to the fragility of connective tissue (SC-D group). There were 2 spontaneous CCFs caused by the rupture of an inflaclinoid aneurysm without any background of connective tissue disorder; these had direct shunts (SA-D group). By this system of grouping and use of abbreviations, each case of CCF can be clearly delineated in terms of its pathogenesis and selection for appropriate treatment.