Pure ovarian neuroendocrine tumors are very rare. Herein, we present a young Iranian woman with a pure primary ovarian neuroendocrine tumor. A 26-year-old female presented with chronic abdominal pain and progressive constipation and was referred to the emergency room. Imaging findings confirmed a mass in the right adnexa. Following the resectional surgery of the ovarian mass, histopathological and immunohistochemistry results disclosed a mixed type of primary ovarian neuroendocrine tumor. The patient did not experience tumor recurrence afterward. Due to the rarity and low prevalence of primary pure ovarian neuroendocrine tumors, the histopathologic diagnosis should be confirmed by an immunohistochemistry study.