Sinonasal lymphoma (SL) is a rare form of extranodal lymphoma. Of 33 SL cases, 14 consecutive diffuse large B-cell lymphomas were treated with CHOP (adriamycin, cyclophosphamide, vincristine and prednisone) or CHOP-like chemotherapy regimen. Ten achieved complete remission (CR) and three achieved a partial remission. With a median follow-up period of 80 months, seven patients relapsed or progressed [one case including central nervous system (CNS) progression]. Four of the relapses involved the CNS. Eight patients were alive, including seven in CR and six patients had died of their lymphoma. This observation strongly suggests that CNS prophylaxis should be used in SL.