Background: The development of lymphomas is accompanied by disorders in the structural and functional organization of the immune system leading to immune deficiency. Such patients are at greater risk of severe SARS-CoV infection. Our purpose was to assess the parameters of cellular immunity in patients with lymphomas with a history of multi-course chemotherapy, therapy with anti-CD20+ antibodies and PCR-confirmed COVID19. Methods: The study included 12 adult patients with lymphoproliferative diseases (non-Hodgkin's large B-cell lymphomas (NHL) - 7, Hodgkin's lymphomas (HL) - 5) with a history of PCR-confirmed COVID-19. All patients underwent 4 to 6 chemotherapy cycles. The relative numbers of the main populations of leukocytes, T- and B-lymphocytes, as well as subpopulations of T-lymphocytes, were assessed in the whole blood collected in K2EDTA anticoagulant using the BD FACSCanto II flow cytometer with a panel of antibodies according to the manufacturer's instructions (Becton Dickinson, USA). Results: Patients with HL showed a number of changes in the parameters of cellular immunity. The content of total lymphocytes and monocytes was reduced in comparison with patients with NHL by 34% and 56%, respectively: 14.3 (11; 17) vs. 21.7 (15.2; 32), and 6.0 (4.8; 7.1) vs. 13.5 (12.9; 13.7), respectively. An increase in granulocytes by 30% was revealed in patients with HL. No differences were found in the content of both general and main populations (CD3+, CD3+CD4+, CD3+CD8+, central and effector memory cells). However, the content of naive CD3+CD4+ and CD3+CD8+ lymphocytes in patients with HL increased by 43% and 62%, respectively. While the number of CD3+CD4-CD8- lymphocytes was 47% lower, the number of CD3+CD4+CD8+, on the contrary, exceeded the values in patients with NHL by 4.6 times. Patients with HL also showed a tendency towards a decrease in the number of NK and NKT-lymphocytes. Conclusions: The increased levels of naive lymphocytes and both populations of memory cells and a sharp increase in double-negative T-lymphocytes and B-lymphocytes in patients with HL could indicate certain characteristics of the disease course affected by COVID-19. The data require additional research and can be used to assess the condition of patients and to predict the therapy efficacy.