Introduction: CD20 is a phosphoprotein expressed on the surface of B lymphocytes. Antibody binding to CD20 causes a reduction in the number of CD20+ cells through three mechanisms: antibody-dependent cell-mediated cytotoxicity, complement-mediated cytotoxicity, and induction of B cell apoptosis. Objective: to know the level of covid antibodies produced in immunosuppressed patients with anti-CD20 drugs after their 4 doses of covid-19 vaccine. Material and Methods: A group of patients with autoimmune pathologies was obtained with inclusion criteria (being in conditions of immunosuppression or autoimmune disease, being able to control them for antibodies, knowing their basic characteristics) and exclusion criteria (lost patients). In the end, 447 patients were included. Variables studied Ac of covid (Quant), age in years, sex, drug, treatment time. Results: In the final analysis of the results, the mean age was 63 years, being somewhat higher in men than in women, and the mean of Ac of covid was 243. In the multiple regression taking the number of antibodies as the dependent variable, the significant variables were: the treatment time coefficient 2.47 (1.5-3.2), and the age of the patients with 1.9 (1.3-2.8). The interactions between the different variables were not significant. Conclusions: The factors that conditioned the level of antibody response in covid-19 vaccination in this type of patient were the time of treatment and age. Keywords: covid vaccination, antibodies, immunosuppression