Meigs' syndrome is a rare clinical entity characterised with ovarian benign tumour, ascites and hydrothorax. Between January '94-September '98 we observed three patients with: ovarian neoformation, light (1 patient), moderate (2 patients) monolateral pleural effusion, moderate (2 patients) and considerable (1 patient) ascites. In all patients the preoperative evaluation (sero-haematologic routine, Ca 125 and other oncologic markers, chest X-ray, abdominal and pelvic ultrasonography, total-body Tc, cytological analysis of pleural and abdominal effusion) was suggestive for malignancy but not confirmed it. So an explorative laparotomy with histological extemporary analysis was performed. The results were: 1 fibrothecomas, 1 fibroma, 1 ovarian inflammation with cystic luteinization areas and fibromatosis uterine. All three patients had a good postoperative course. The symptomatology and the effusions disappeared 7-10 days after operation. The first two cases were diagnosed as classic Meigs' syndrome, the third one, instead, as a pseudo-Meigs's syndrome. In conclusion the A.A., according to literature and their experiences, underline: 1) an ovarian mass with pleural and abdominal effusion not always represents an advanced malignancy; 2) even if elevated Ca 125 value is usually associated to a ovarian malignancy, there are some benign lesions in which we observed elevated level of this marker 3) the removal of the ovarian mass is the only resolutive treatment for these patients.