Gliomatosis peritonei is a rare occurrence, characterized by miliary implantation of predominantly mature glial tissues on the surface of the peritoneum, in association with a mature teratoma of the ovary. Although grossly mimicking carcinomatosis, a mature gliomatosis peritonei is generally benign. Conservative surgical treatment without adjuvant therapy is indicated. We describe 2 cases of gliomatosis peritonei. One case, associated with unilateral ovarian teratoma, was treated conservatively with a fertility-preserving operation. The other, associated with bilateral teratoma, was treated with an extensive operation with total hysterectomy. Neither patient had experienced recurrence by the 8-year follow-up.