Introduction: Osteoma of the paranasal sinus is a rare and benign tumor that develops slowly when therapy becomes mandotory, it is necessarily surgical. Results: We report 38 cases of osteoma, operated by external approach in 36 cases and endonasal approach in 2 cases. The osteoma involved the frontal sinus in 27 cases, ethmoid in 5 cases and the junctional zone in 6 patients. The follow up patients was correctly done in 36 cases. The functional results were satisfying without recurrence in 34 of them (follow-up: 18 months). In the other 2 patients a recurrence was diagnosed. Conclusion: sinus osteoma is a benign tumor. Symptomatic form does been treated by a surgery. The approach depends on the location of osteoma and CT-Scan may guide the choice Key words: Osteoma, sinus, external approach, endonasal approach.