Introduction. Ovarian cancer is the leading cause of death from gynecological malignancies: the one-year relative survival rate with stages 3 and 4 of the disease is 20%. The results of treatment remain unsatisfactory, which dictates the need to find new methods of treatment. The aim of the study was to evaluate the effectiveness of the use of HIIH (hyperthermic intraperitoneal intraoperative chemoperfusion, HIPEC) in patients with the diagnosis of: ovarian cancer IIIA-From the stage of the disease.Materials and methods. 117 cases of stage IIIA-C ovarian cancer treated at the Chelyabinsk Regional Clinical Center of Oncology and Nuclear Medicine from January 2014 to March 2021 were retrospectively studied. All patients underwent 3 cycles of neoadjuvant chemotherapy (NAPHT) according to the paclitaxel+carboplatin (PCb) scheme, followed by surgical treatment to the extent of maximum cytoreductive surgery. Two study groups were formed: 1 — cases with GIIH (N=57), 2-without GIIH (N=60). On the 14-16 day after the operation, all patients underwent 3 cycles of adjuvant chemotherapy according to the PCb scheme.Results. A significant increase in overall survival was found in the first group of patients with HIPEC. This technique allows to increase the survival rate of patients for 14 months at stage IIIA-B (p<0.05). At stage IIIC, there was no statistically significant difference in the survival rate of patients. There was a tendency to increase the survival rate by 5 months (p>0.05), which is associated with the pronounced prevalence of the tumor process and the technical impossibility of removing the tumor. Discussion. The concentration of drugs in the abdominal cavity and in the blood plasma significantly differs due to the functioning of the peritoneal-plasma barrier, which leads to a lower toxicity in comparison with systemic chemotherapy, and therefore allows you to give a large dose of the drug with fewer adverse events, and the fact of hyperthermia (42°C) has a positive effect on the effectiveness of intraperitoneal chemotherapy. To date, this method has not been included in the clinical recommendations on the territory of the Russian Federation, but data from foreign literature, including randomized trials, have shown the high effectiveness of this method.Conclusion. The results obtained in the course of our study demonstrate the effectiveness of this technique, in the form of an increase in overall and relapse-free survival with acceptable toxicity.