We present two cases of gastrointestinal stromal tumors (GISTs) that presented as pelvic masses. These tumors can present diagnostic problems and they may be difficult to discover preoperatively. GISTs are neoplasms that can be diagnosed utilizing immunohistochemistry, especially detecting CD117 (c-kit) reactivity along with associated histological features. GISTs, should be considered in the differential diagnosis of ovarian tumors especially when imaging studies and rectovaginal examination findings are inconclusive and vague. Histologic diagnosis of these tumors are important considering the efficacy of tyrosine kinase inhibitor therapy after surgery in such cases.