Two cases of Meigs' syndrome are reported, one following an ovarian fibrothecoma and the other an ovarian fibroma. The benign condition was suggested prior to surgery in one of the two patients because of a solid tumor of the ovary without peritoneal implant on CT-scan, and no malignant cells in ascitic fluid and on a fine needle biopsy. To differentiate this benign pathology from a malignant process enables to avoid useless surgical procedures. Preoperative evaluation, including serum CA 125 level, ultrasound examination and CT-scan, allows rarely to suggest the Meigs' syndrome. Nevertheless, this syndrome may be suspected when faced with an important pleural effusion, a very elevated CA-125 serum level, a negative cytologic examination of the ascitic effusion and no peritoneal implant on CT-scan.