Post- COVID is characterized by a decrease in the patients’ quality of life, a tendency to hemocoagulation. Symptoms of post- COVID are diverse and difficult to classify. Purpose : Study of neutrophil extracellular traps (NETs) in post-COVID patients to clarify the mechanisms of damage. Patients and methods : Two groups of patients with postCOVID were examined. In the first group (21 patients), COVID-19 treatment was carried out in a hospital, in the second group (20 patients) - on an outpatient clinic. The comparison group consisted of 10 patients with acute appendicitis, the control group consisted of 20 healthy people. Neutrophils were isolated using gradient centrifugation. NETs was visualized using fluorescence microscopy with SYBR Green dye (Evrogen; Russia), which specifically interacts with double-stranded DNA. Purine nitrogenous bases (PNB) were determined by the color reaction method based on their interaction with silver nitric acid.