The article presents a case of a 68-year old male admitted to coronary care unit because of acute coronary syndrome without ST segment elevation. In coronary angiography a lesion in the left main coronary artery (LMCA) is found. Intravascular ultrasound (IVUS) examination confirms the diagnosis of the ruptured plaque with the presence of thrombus. Because of the well preserved lumen area a decision to continue intensive pharmacotherapy is made. Follow-up angiography and IVUS show a complete resolution of thrombus. The article discusses different management strategies in patients with confirmed ruptured plaque in LMCA.