BACKGROUND: Recent articles have published guidelines regarding the role of endoscopic surgery in the removal of frontal sinus osteomas. These guidelines recommend the endoscopic approach for small osteomas but recommend an osteoplastic flap for larger tumors. This study presents a series of endoscopically resected tumors both large and small. METHODS: Retrospective chart reviews were performed. Charts were reviewed of all patients who underwent surgical resection of a frontal sinus osteoma from 1998 to 2008. Sinus CT scans were reviewed and each tumor was staged according to Kennedy's grading system proposed in 2005. RESULTS: Twenty-three patients, 8 with a grade IV tumor, 6 with a grade III tumor, and the remaining with a grade I or II tumor, underwent endoscopic resection of a frontal sinus osteoma. In 15 patients a modified Lothrop procedure was performed for tumor removal. In addition, a blepharoplasty incision was used in one patient for removal of a large orbital extension of the tumor and another underwent an enlarged frontal sinus trephine performed via a browline incision. In the remaining patients a frontal sinusotomy with minitrephination provided enough access for tumor removal. Over an average follow-up of 36 months no recurrences were noted. Symptoms improved in all but one patient. There were no postoperative complications. CONCLUSION: Endoscopic resection of both large and small frontal sinus osteomas is feasible. In this article we have shown successful removal of large osteomas that fill the entire frontal sinus with the modified Lothrop procedure.