Acute type A aortic dissection (ATAAD) constitutes a life-threatening aortic pathology with significant morbidity and mortality. Without surgical intervention the usual mortality rate averages between 1-2 % per hour. Thus, an early diagnosis of ATAAD is of pivotal importance to direct the affected patients to the appropriate treatment. As a consequence, we investigated whether aggrecan (ACAN) is a potential biomarker for diagnosing ATAAD. Our investigation showed that ACAN mRNA expression is highest in aortic tissue from ATAAD patients. Mean ACAN protein concentration showed a significantly higher plasma concentration in ATAAD patients (38.59 ng/mL) compared to plasma of patients with thoracic aortic aneurysms (4.45 ng/mL), patients with ST-elevation myocardial infarction (11.77 ng/mL) and healthy volunteers (8.05 ng/mL). Cardiac enzymes like creatine kinase MB and cardiac troponin T showed no correlation with ACAN levels in ATAAD patients. Receiver-operator characteristics (ROC) curve analysis for ATAAD patients versus control subjects revealed an area under the curve of 0.947 and an optimum discrimination limit of ACAN plasma levels at 14.3 ng/mL with a corresponding sensitivity of 97 % and specificity of 81 %. According to our findings ACAN is a reliable potential biomarker in plasma samples to detect ATAAD with high sensitivity and specificity.