Acute Type I aortic dissections are fast progressing highly mortal vascular emergencies if management delays. In this particular paper we report a case with a Type I aortic dissection mistreated for first 2 hours as thrombotic AMI, and aortic dissection diagnosis confirmed and treated surgically immediately. 59 years old male patient admitted to emergency room with sudden onset chest pain. Patient was seen by cardiologist and with NSTMI diagnosis admitted to Coronary ICU. With the suspicion of aortic dissection patient was scanned with contrasted thoraco-abdominal CT. Exam revealed subtotal occlusion of ascending aorta by flap of De Bakey Type I aortic dissection. In conclusion aortic dissection should be considered in differential diagnosis of chest pain. Clinical suspicion aortic dissection is key point of diagnosis and immediate confirmation may be life saving.