Pseudomixoma Peritonei (PMP) is an uncommon neoplasm characterised by mucinous ascites and multifocal amorphous mucous substances involving the peritoneal surface, omentum and bowel loops. Although the origin of the Pseudomixoma Peritonei is still unclear, it could be due to the perforation of an ovarian mucinous cystoadenoma or an appendiceal mucocele. The further pelvic dissemination of the endotumor material, which adhere itself into the peritoneal surface, may induce an intra-abdominal transformation of the peritoneal mesothelium into mucin-producing tissue. A case of Pseudomyxoma Peritonei (PMP) which occurred in a young woman is reported.