We have analyzed the clinical data of 27 cases of sphenoid inflammatory neoplasms and sphenoid sinus tumors including inflammations (12 cases), benign tumors (10 cases) and malignant tumors (5 cases). The characteristics of sphenoid inflammatory neoplasms were compared with those of sphenoid sinus tumors. On CT scanning and magnetic resonance imaging (MRI) we found that sinusitis resulted in much less bony erosion than tumors on CT scanning and that the T2-signal intensity on MRI increased much more in sinusitis than in tumors. We have discussed the indications of various operative approaches and suggested that the approach of external ethmoidectomy is a method of choice.