Therapeutic embolization of juvenile angiofibromas was performed in 15 boys, aged 12-18 yr, 11 of whom subsequently underwent surgery. Intraoperative blood loss was reduced from an average of 2,400 ml in nonembolized patients to 800 ml after embolization. Angiography is of value to confirm the diagnosis prior to excision and to delineate the extent of the tumor. Embolization may be performed at the same sitting as a presurgical adjunct or possibly as a definitive or palliative therapeutic method. The embolization procedure is discussed in detail, emphasizing techniques and potential hazards of such procedures.