Papillary serous carcinoma of the peritoneum is indistinguishable from ovarian serous cancer in terms of histology, histochemistry, immunohistology and ultra-structure. The process involves the peritoneum diffusely, sparing or only superficially invading the ovaries. The clinical presentation is similar to advanced ovarian cancer, but the ovaries are of normal size. Histopathologically, the disease must be differentiated from malignant mesothelioma through appropriate studies. Treatment entails total abdominal hysterectomy, bilateral salpingectomy, oophorectomy, and cytoreductive surgery followed by platinum-based chemotherapy. Response and survival rates are similar to those in serous ovarian cancer.