INTRODUCTION: Percutaneous transvenous embolization (TVE) using coils is a well-established treatment of cavernous sinus dural arteriovenous fistula (CSdAVF). However, it is sometimes difficult to achieve complete occlusion by coil embolization. In these two cases, we were able to obtain complete angiographic obliteration of the fistulas without complications by means of percutaneous TVE using n-butyl-cyanoacrylate (NBCA) after we failed when TVE using coils. Case 1: An 89-year-old woman presented with double vision. She was diagnosed as Barrow type D right CSdAVF draining only to the cortical vein. We treated the patient by TVE using coils, but the microcatheter was withdrawn before complete occlusion was attained. The repositioning of the microcatheter was difficult, so we used 30% NBCA for TVE, and obtained complete obliteration of the fistula. Case 2: An 87-year-old woman presented with right exophthalmos, and chemosis. She was diagnosed as Barrow type C right CSdAVF draining only to the right superior ophthalmic vein with very slow flow. We planned to treat her, using TVE with coils, but we could place only 3 coils and obtained only partial obliteration of the fistula. So we additionally used 25% NBCA for TVE, and obtained complete obliteration of the fistula. CONCLUSION: Compared to TVE using coils, TVE using NBCA gives rise to many problems, but, we can use NBCA as a second option if TVE using coils results in only partial obliteration as in these cases.