We report here on a case of peripheral T-cell lymphoma of the ovary as the initial manifestation of extranodal disease. A 45-year-old woman presented with an incidentally detected, ovarian mass. Contrast-enhanced CT scans showed a 6x5.3 cm diameter, heterogeneously enhancing mass in the right adnexa that invaded the adjacent uterus. An exploratory laparotomy revealed a solid mass in the right adnexa, which invaded the uterine cornus. Histological diagnosis was made as a peripheral T-cell lymphoma of the ovary.