To evaluate findings for patients with carotid cavernous fistulae or dural arteriovenous fistulae (AVFs) who underwent transvenous embolization via different transvenous approaches. Retrospective analysis of data for 31 patients (age range, 17-81 yr; mean age, 59.3 yr) with carotid cavernous fistulae (n = 6) or dural AVFs (cavernous sinus [CS], n = 11; transverse/sigmoid sinus, n = 14) was performed. The AVFs were treated with coils via different transvenous approaches, in 56 procedures. Doppler ultrasonography and time-resolved, two-dimensional, magnetic resonance projection angiography were performed to confirm the treatment. The mean clinical follow-up period was 32.5 months. A total of 34 transvenous procedures were performed for 17 AVFs of the CS. Eleven patients with AVFs of the CS (63%) were cured with respect to clinical symptoms, and six patients experienced improvement (37%). The approach via the internal jugular vein and inferior petrosal sinus (n = 15) was possible in 60% of cases, with complete occlusion of the fistula in 78% of cases. With the approach via the facial vein (n = 8), there was a 50% success rate. The superior ophthalmic vein approach (n = 5) was associated with a high rate of technical success (100%), with a rate of complete fistula occlusion of 80%. We encountered complications, with transient morbidity, in four cases (23.5%). For 14 dural AVFs of the transverse/sigmoid sinus, 22 transvenous procedures were performed; 12 patients were cured (85.7%) and 2 experienced improvement (14.3%). The technical success rate was 86%, with complete occlusion in 42% of cases. Minor complications occurred in six cases (42.9%) but did not lead to permanent morbidity. Transvenous treatment of CS and transverse/sigmoid sinus AVFs can be effective if all transvenous approaches, including combined surgical/endovascular approaches, are considered.