Over a 2-year period, 21 patients with clinical and radiologic evidence of persistent or recurrent frontal sinusitis who had a prior ethmoidectomy and/or frontal sinusotomy underwent an endoscopic Lothrop procedure. The patients' chief complaints were headaches (13), nasal obstruction and/or purulent rhinorrhea (4), orbital abscess/cellulitis (2), anosmia (1), and cough (1). Preoperative frontal headaches were present in 19 patients. The common frontal ostium remained patent (> 50% of intraoperative size) by flexible fiberoptic examination and transillumination 2-24 months postoperatively in 12 of 21 patients (57%). Eighteen of 21 patients (86%) had improved or resolved chief complaints. All but 4 of 19 patients (21%) with preoperative frontal headaches had improved or resolved symptoms. Two patients required additional surgery during the follow-up period. The endoscopic Lothrop procedure is a viable option before frontal sinus obliteration in patients with recurring frontal sinusitis who have failed conventional endoscopic techniques. The surgical technique and results will be presented.