There is still some skepticism about endoscopic endonasal resection of inverted papillomas. We conducted a long-term retrospective study and examined 104 patients (82 male, 22 female) with inverted papilloma who were operated at the ENT-Department of the University of Erlangen between 1974 and 1997. The endoscopic approach was chosen in each case, either alone or in combination with external approaches. In 64.4% (67 cases), tumors of all T-classes were resected by endoscopic approach alone (T1:17.9%, T2:23.9%, T3:41.8%, T4:16.4%). For the rest of the patients an additional transoral and transfacial approach was necessary due to difficult tumor localization (T2:24.3%, T3:29.7%, T4:45.9%). The mean age of the patients was 55 years. The recurrence rate after primary endoscopic endonasal sinus surgery was 22.4% (15/67) and after combined endoscopic and external surgery 16.2% (6/37). Second salvage surgery after endoscopic sinus surgery was performed again endonasally in 46% (7/15) and externally in 53.3% (8/15). The recurrence rate after the endonasal approach was now 57.1% (4/7) and 50% (4/8) after external surgery. Third salvage surgery was performed again endoscopically in four cases and externally in four cases. The recurrence rate in both groups was 50% each, so that up to six operations, either endoscopically or externally, were necessary for complete tumor resection. The longest period for a tumor recurrence was 3.4 years after endoscopic sinus surgery and 9 years after combined endoscopic and external surgery. A tumor recurrence after endoscopic endonasal sinus surgery that could not be managed endoscopically again occurred in 12%. Tumor localization is the limiting factor for endoscopic endonasal sinus surgery of inverted papilloma. However, in 64.4% of cases, endoscopic endonasal sinus surgery alone was performed successfully without any loss of one patient. Long-term follow-up is necessary since the recurrence of tumor can happen after a long time. Endoscopic endonasal sinus surgery of inverted papilloma is safe and should be preferred due to its minimal invasive character.