Paragangliomas are rare tumors arising from the chromaffin cells in the autonomic nervous system. While they both occur most frequently along the paraaortic chain, paraganglioma and ovarian carcinoma very rarely occur together. A 61-year-old, post-menopausal woman visited our hospital, with complaints of abdominal pain and genital bleeding. Image analysis showed a 21 x 18 x 10 cm ovarian mass, and a 38 mm tumor at the paraaortic lesion. First, she underwent bilateral salpingo-oophorectomy. Serous papillary cystadenocarcinoma of the left ovary was found, and so a second surgery was performed. The paraaortic tumor was completely eliminated in spite of fluctuating blood pressure intraoperatively. Microscopic examination revealed that the paraaortic tumor was paraganglioma. She was ultimately diagnosed as having ovarian carcinoma stage Ia (FIGO) with coincident paraganglioma. If blood pressure fluctuation is observed during dissection of the paraaortic lymph node, paraganglioma should be suspected and blood pressure must be carefully controlled.