Balloon sinus dilation (BSD) is generally accepted as a safe alternative to traditional sinus surgery. It is a unique technique designed to potentially minimize complications associated with traditional functional endoscopic sinus surgery (FESS). We present a case in which a 65-year-old man experienced a cerebrospinal fluid (CSF) leak in the ethmoid roof that was visualized instantly after balloon dilation in a revision sinus surgery. In this case report, we discuss the causes of CSF leaks and explain in detail the immediate endoscopic repair with a collagen matrix. Also, literature is reviewed on the safety of BSD versus traditional FESS. Postoperative-ly, the patient has been without CSF leak and remains symptom free. CSF leak is a rare but major complication during both FESS and BSD. As BSD use increases, its complication profile will become clearer when used alone, in conjunction with FESS, and/or during revision surgery. Although BSD is considered a benign procedure, one should be cautious when using it in revision sinus surgery.