We describe a patient who developed bilateral cavernous sinus septic thrombosis secondary to a suppurative lesion on the left cheek. Despite clinical improvement, left oculomotor symptoms recurred suddenly. A carotid artery aneurysm within the cavernous sinus was diagnosed by means of magnetic resonance imaging and confirmed by digital angiography. Follow-up angiograms showed an initial decrease in the aneurysm size, with subsequent enlargement. A latex contrast-filled balloon was successfully placed within the aneurysm, preserving the carotid parent artery blood flow. Our case illustrates the usefulness of the detachable balloon technique in the treatment of bacterial aneurysms of the cavernous sinus as an alternative treatment to carotid artery ligation.