A series of 1,077 intranasal ethmoidectomies (825 with sphenoid sinusotomies) was performed in 600 patients over a 15-year period at The Mount Sinai Medical Center. The technique is a modification of the classical operation originally proposed by Yankauer.1 The rate of significant complications was 1.1%. A subset of 90 patients underwent 166 procedures and were followed an average of 3.5 years. The patients were analyzed according to whether the disease was focal or diffuse, infectious or polypoid, and whether asthma was present. The surgical success rate was 88% in nonasthmatics, but dropped to 50% in asthmatic patients despite total sphenoethmoidectomy. This underscores the importance of this condition as a biological modifier of surgical prognosis. Accordingly, a system of classification of sinus diseases is proposed based upon disease extent and type and whether asthma is present.