The authors present the experience of ligation of transverse or sigmoid sinus in the surgical removal of petroclival meningiomas. We reviewed the medical records and venograms of 14 patients with petroclival meningiomas, in whom the intraoperative ligation of transverse or sigmoid sinus had been done at our hospital between 1986 and 1999. All patients passed the intraoperative test clamping of the sinus. The drainage pattern of confluence of Herophili was classified into four types: type A, confluence and equal drainage on both transverse sinuses; type B, confluence and non-dominant transverse sinus on the tumor side; type C, confluence and dominant transverse sinus on the tumor side; and type D, unilateral transverse sinus only. Among the 14 cases, four cases were in type A, five cases in type B, and two were type C. There was no evidence of brain swelling after intraoperative test clamping of the sinus for more than 30 min. None of the patients experienced postoperative complications related with sinus ligation. Our observation suggests that the transverse or sigmoid sinus ligation is tolerable to patients who show the drainage patterns of type A, type B, and type C, if the test clamping proves to be safe.