Patients with COVID-19-associated pneumonia (COronaVIrus Disease 2019) have a higher risk of thrombosis. Due to the issue’s urgency, a clinical case of thrombosis of the pulmonary trunk, lobar, segmental, subsegmental, and small branches of the right and left pulmonary arteries casing infarct pneumonia after SARS-CoV-2 infection (Severe Acute Respiratory Syndrome-related) is presented. Patient S., born in 1980, on April 18, 2023, was hospitalized for several hours at the Republican Cardiology Dispensary of the Chuvash Republic with the following clinical diagnosis: severe COVID-19 infection. Complications of the underlying disease: COVID-associated pneumonitis, alveolitis, pulmonary embolism. The patient was brought to the hospital by an ambulance team. She complained of shortness of breath even with slight exertion, cough, chest pain, and fever up to 38.5°C. Chest computed tomography showed signs of bilateral diffuse COVID-associated pneumonitis and alveolitis with a lesion area of 62%. There were signs of pulmonary trunk thrombosis and infarct pneumonia of the right lung lower lobe. SpO2 was 73%. The diagnosis of COVID-19 was confirmed by a polymerase chain reaction in a nasopharyngeal smear. The NEWS2 score was 11. Complete blood count: white blood cells 14.2·109/L (RR 3.39—8.86·109/L), lymphocytes 16% (RR 19—37%), erythrocyte sedimentation rate 72 mm/h (RR 2—15 mm/h). Blood chemistry: C-reactive protein 24.5 mg/L (RR 0—6 mg/L), lactate dehydrogenase 544.0 U/L (RR 10.0—250.0 U/L), D-dimer 642 ng/mL (RR 0—250 ng/mL). Despite the treatment, the patient died. At necropsy, signs of recurrent thrombosis in the vascular bed of the lungs causing infarct pneumonia of the right lung lower lobe were revealed. It is concluded that the patient with COVID-19 developed a rapid death, having relatively mild disease with no predisposing risk factors for venous thrombosis and thromboembolism.