Pseudo-Meigs' syndrome is a rare condition that includes hydrothorax and/or ascites secondary to ovarian neoplasms other than benign primary tumors. A 67-year-old woman presented with ascites, hydrothorax, left ovarian mass and elevated CA-125 level. The mass was removed and revealed serous cystadenocarcinoma. The immediate and complete resolution of symptoms and rapid decline of CA-125 level to normal value was achieved post-operatively. One month after surgery, she had no evidence of ascites or pleural effusion. We report Pseudo-Meigs' syndrome associated with ovarian serous cystadenocarcinoma and elevated CA-125 level.