Circulating tumor cells (CTCs) are cells released from the primary tumor and circulating in peripheral blood. CTCs are an important element in the process of understanding the biology of metastases. In the future CTCs may be used as biomarkers for the assessment of neoplastic process progression and recurrence. The CTCs presence in peripheral blood was described in various tumors, and the possibility of their use in clinical procedures was demonstrated. The appearance of CTCs is a sign of metastasis formation and its spread via the circulatory system. Ovarian cancer is a special type of tumor as it grows and recurs mainly in the abdominal cavity. Despite advances in therapeutic methods, more than half of the patients with ovarian cancer exp...