Introduction. When evaluating the performance of public health institutions in the Moscow region that provide all types of medical care to cancer patients, an increasing role is assigned to the degree of satisfaction of citizens with the quality of medical services provided. Goal. This article presents basic approaches to assessing the main causes of dissatisfaction of patients with malignant neoplasms with regard to the medical care provided on the basis of appeals from these citizens, as well as an independent assessment of the quality of medical services provided on departmental Internet portals. Materials and methods. The main information for assessing indicators of low satisfaction with medical care provided to people with cancer was obtained from complaints and / or appeals from citizens, as well as from the protocols of targeted surveys and acts of departmental inspections of medical organizations for the period 2018-2019. The primary causes of patients 'dissatisfaction with medical care were evaluated and recommendations were offered to medical organizations on how to organize specialized work with cancer patients, as well as to prevent patients' dissatisfaction with the medical care provided. Results. The first place can be attributed to the lack of medicines for chemotherapy prescribed by the attending doctor and subject to free receipt by the patient in the pharmacy network (in 2019 – 20.9 %, in 2018-19.7 %). There is also an increase in the number of appeals/complaints from cancer patients and / or their representatives, who are recommended the traditional treatment regimen as the main treatment and are not prescribed targeted drugs based on genetic studies. In 2019, the share of such requests was 17.2%, in 2018-10.6%. Particular attention is drawn to the increase in the number of cases of refusal of medical care – 10.6% of requests in 2019 and 7.7% in 2018. Another indicator of "systemic" requests – the priority for receiving radiation therapy as prescribed by a doctor and / or a consultation of doctors – this problem was noticed in 10.4% of citizens ' requests (in 2018 – 10 %). In 2.5% of citizens ' requests in 2019 (in 2018 – 2.2%), cancer patients complained of non-compliance by medical workers with the basics of ethics and deontology (rudeness and rudeness of medical personnel). Conclusions. For certain medical organizations, there is a constant increase in the number of complaints about dissatisfaction with the medical services provided. And, considering the fact that medical assistance regardless of its type and form is carried out in specific health organizations, it must be concluded that in the health institutions of the state system have a need for priority actions to analyse the reasons of dissatisfaction of the population receiving medical services, further development and obtaining feedback from patients by using forms, such as "hot line", the use of the official sites of medical organizations, Internet portals.