Endonasal endoscopic surgery of the paranasal sinuses for chronic sinusitis has been accepted as the treatment of choice by many authors, but detailed evaluation of the results is often lacking. Of a consecutive series of 220 patients with diffuse chronic paranasal polyposis who had undergone endoscopic pan-sinus operations, 90 were re-examined endoscopically after 1-7 years. Normal respiratory mucosa was found in 57% of cases and minor circumscribed mucosal hyperplasia in a further 25%. Unsatisfactory healing or recurrence of polypi was found in 18%. A questionnaire completed by all 220 patients showed that 49% were completely relieved, 33% reported a marked improvement, 12% remained unchanged, and 6% claimed a deterioration. Of those patients with polyposis and bronchial asthma, 57% achieved marked relief. The very low incidence of surgical complications after complete endoscopic ethmoidectomy should be emphasized.