High-risk pulmonary thromboembolism (PTE) is an emergency clinical condition with high mortality. High-risk pulmonary thromboembolism is generally seen in immobile patients, elderly, have malignancies, and have a long-term travel history. Our aim here is to emphasize that high-risk pulmonary thromboembolism may also occur in young patients. Considering the symptoms and risk factors such as oral contraceptive use, obesity, and operation history, PTE can be detected with Pulmonary Computed Tomography-Angiography (CTPA) or Ventilation Perfusion Scintigraphy (V/Q) when necessary. It should be verified that it is not. Genetic mutation, obesity, oral contraceptive use, and previous operation history were accepted as risk factors in the young patients we treated and followed up with high-risk Pulmonary Thromboembolism presented here. After the diagnosis of pulmonary thromboembolism was made at the first stage in our patients who applied to the emergency department, the risk group was determined by taking into account the current guidelines. Three patients considered to be at high risk were evaluated for thrombolytic therapy. Two patients without contraindications were given a full dose, and one patient was given a half dose of thrombolytic. After being monitored in intensive care for the first 24 hours, they were taken to the service. Due to their young age (<45 years), their thrombophilia panel was checked. Anticoagulant treatments were started and follow-ups were planned at 3 months, 6 months, and 1 year after discharge. During the follow-up visits, CTPA, echocardiography (ECHO), and lower extremity Doppler ultrasound imaging were performed.