In the studied cohort of 176 patients, we did not obtain a reliable result indicating a higher risk of thrombotic complications when taking therapeutic doses of anticoagulants in carriers of the genetic markers for thrombophilia, including G1691A in the FV gene, C677T and A1298C in the MTHFR gene, G20210A in the FII gene, and (-675) 4G/5G in the PAI-I gene for COVID-19 disease relative to patients without these markers. Here, MTHFR is linked to Rare hereditary thrombophilia.