BACKGROUND: Ovarian carcinoids are exceptionally rare. This report discusses an unprecedented case of a primary ovarian mixed insular and trabecular carcinoid, presenting with constipation. CASE PRESENTATION: A 47-year-old female presented with a four-month history of constipation. A comprehensive abdominal CT with contrast revealed a large mass in the pelvic region, measuring 8.6×9.7×9.3cm. Consequently, the patient was referred for further evaluation. Intraoperative exploration uncovered a 10.0×9.0 cm mass in the left ovary. Initial histopathological assessment suggested a sex cord-stromal cell tumor, leading to a left ovariectomy and bilateral salpingectomy. Final histopathological analysis post-surgery identified the mass as a mixed insular and trabecular carcinoid. The patient was diagnosed with stage Ia, T1aN0M0 primary ovarian mixed insular and trabecular carcinoid. CONCLUSIONS: Diagnosis of carcinoids predominantly relies on postoperative histopathological examination. As of now, There is no established standard treatment, emphasizing the necessity for ongoing patient monitoring.