Pseudo-Meigs' syndrome accompanied by massive ascites in uterine leiomyoma is rare. We encountered a rare case of a 37-year-old, nulliparous woman with a lower abdominal tumor and severe abdominal distention due to massive ascites. Serum cancer antigen 125 and vascular endothelial growth factor levels were elevated to 1007.9 U/mL and 103 pg/mL, respectively. She was tentatively diagnosed with ovarian cancer. Emergency concentrated ascites re-infusion therapy was performed to improve dyspnea, abdominal pain, and her preoperative respiratory condition. Concentrated ascites re-infusion therapy eliminated dyspnea and abdominal discomfort without decreasing serum albumin levels. The patient underwent laparotomy, which revealed a fist-sized pedunculated uterine leiomyoma arising from the right uterine fundus. Myomectomy was performed. Pseudo-Meigs' syndrome mimics advanced ovarian cancer due to massive ascites and markedly elevated serum cancer antigen 125 and vascular endothelial growth factor levels. Concentrated ascites re-infusion therapy was effective in improving the subjective symptoms of pseudo-Meigs' syndrome and the patient's preoperative condition.