Pseudo-Meigs' syndrome is used to describe cases of ascites and/or pleural effusion associated with ovarian neoplasms other than benign tumors, which improve after removal of the ovarian lesion. We present three cases of pseudo-Meigs' syndrome secondary to ovarian metastasis from colorectal cancer. In case 1, the patient has severe dyspnea and hypoxia due to massive right pleural effusion; therefore preoperative thoracic drainage was needed. In case 2, the patient needed paracentesis every two or three days to improve abdominal distension. After two courses of 5-fluorouracil, levofolinate, and oxaliplatin (mFOLFOX6), her ascites could be controlled by diuretics without aspiration and her general condition improved. Then she underwent operation. In case 3, the patient developed a massive pleural effusion and ascites coincident with a rapid enlargement of ovarian tumor after resection and adjuvant chemotherapy for rectal cancer. In all cases, pleural effusions and/or ascites resolved and general conditions and daily activities of the patients improved after oophorectomy. They are all currently in good health without recurrence of pleural effusion or ascites. In patients with suspected pseudo-Meigs' syndrome secondary to ovarian metastasis of colorectal cancer, operation including oophorectomy may reduce pleural effusions and/or ascites and improve the general condition.