No data in the literature report the specific invasion of the orbit from ethmoidal tumors, although such a pattern of involvement of the orbit frequently occurs because of the thin lamina papyracea separating the two structures. From January 1986 to January 2003, 38 patients with untreated primary ethmoidal malignancies were observed at the Unit of Maxillo-Facial Surgery of the University "La Sapienza" in Rome. Personal data were obtained from review of the personal clinical file of each. Orbital invasion was present in 24 patients with ethmoidal malignancy. Three stages of orbital invasion were identified. The average overall survival, with the Kaplan-Meyer method, was 61.4% after 1 year and 51.1% at 5 and 10 years. Intracranial involvement is the main element for short-term negative prognosis. Orbital exenteration is fundamental if grade III orbital invasion occurs because it ensures an improvement of the disease-free survival.