Abstract: Objective To compare the clinical characteristics, clinical course and laboratory findings of diagnosed and misdiagnosed cases of aortic dissection (AD). Methods The data of 33 cases of AD were collected for a retrospective review. All the patients underwent examination with X-ray and B-type ultrasound, and diagnosis of the suspected cases was further verified CT and magnetic resonance imaging according to the criteria of presence of false lumen or free valves. Diagnosis of AD was established in 18 of the 33 patients, including 14 male and 4 female patients aged from 20 to 79 years with a mean of 55.8±11.4 years. Misdiagnosis occurred in 15 patients including 12 male and 3 female patients aged 22-75 years with a mean of 56.2±10.8 years. Results No significant differences were found between the diagnosed and misdiagnosed groups in terms of age, sex, hypertension, coronary heart disease, chest pain, heart murmur, pericardial effusion, pleural effusion, average systolic and diastolic pressure, white blood cell count, creatine phosphokinase (CK) and its isoenzyme CK-MB, or De Bakey type Ⅲ (P>0.05). Significant differences in peripheral large blood vessel murmur, asymmetric blood pressure of the arm and leg, ST segment variation, arrhythmia, and De Bakey typesⅠ and Ⅱ were noted between the two groups (P<0.05). In cases misdiagnosed as acute coronary syndrome, ST segment variation, creatine kinase, arrhythmia, and white blood cell count were significantly different from those in cases of diagnosed as AD (P<0.01), but CPK-MB and cardiac troponin I were comparable. Conclusion The initial symptoms, disease course, cardioelectrographic changes and creatine kinase of AD can be easily confused with those of acute coronary syndrome, and special attention should be given to their differentiation.