Introduction: Cancer of the appendix is an uncommon disease and is typically identified incidentally during appendicectomy. Bilateral ovarian metastases may occasionally occur in mucinous adenocarcinomas of appendix mimicking primary ovarian malignancies and can present a diagnostic challenge. The prognosis is poor as it is usually diagnosed at an advanced stage, either due to a low threshold of suspicion and also due to difficulties in diagnosis before surgery. Here we are reporting such a case of occult appendiceal adenocarcinoma which presented clinically as primary ovarian malignancy. Staging laparotomy revealed large bilateral ovarian tumors of FIGO Stage III, with presumed appendiceal implants. Histological examination revealed transmurally infiltrating Mucinous Adenocarcinoma of the appendix with mesoappendiceal invasion and serosal involvement, with lymphovascular invasion with secondaries to bilateral ovaries and omentum. Immunohistochemical staining revealed positive for CK 20 and CDX2 and negative staining for CK 7. The diagnosis of a primary mucinous adenocarcinoma of Appendix with bilateral ovarian metastasis was confirmed with pT4aG2pNxpM1c; TNM stage IV. The patient is planned for right hemicolectomy, total peritonectomy and hyperthermic intraperitoneal chemotherapy (HIPEC). Conclusion: Although adenocarcinoma of the appendix is uncommon, they should be considered in the differential diagnosis of intraabdominal masses, as the treatment modalities vary. © 2024 Elsevier B.V., All rights reserved.