Background: Ovarian carcinoma is a malignant tumor with a poor prognosis. Due to the late onset of the first symptoms, most patients present with already advanced disease—at stage III or IV, which significantly reduces life expectancy. Despite advancements in surgical treatment, in particular, in chemotherapy, the mortality remains high, only slightly over 40% of female patients can expect a 5-year survival rate. Case: We report on an extremely rare case of a documented 45-year survival in serous ovarian cancer patient. The first diagnosis was confirmed in 1978, and she was treated surgically for histologically confirmed ovarian serous carcinoma. The first recurrence appeared in 2013 and was histologically confirmed in an open abdominal biopsy. The patient was successfully managed using carboplatin/paclitaxel chemotherapy and remained in remission. The second recurrence appeared in 2016 and was well managed with chemotherapy. In 2023, the histological examination of laparoscopic biopsy confirmed serous ovarian carcinoma relapse. The comparison of all biopsy samples proved the recurrence of the same tumor and excluded a secondary disease. Conclusions: This rare case of unusually long survival in serous ovarian cancer patient indicates that some patients may have a much better prognosis than typically observed. Advances in genetic determinations are needed to better understand the biology of this tumor to identify patients with the perspective of better survival.