OBJECTIVES: Aortic dissection is complex. Imaging and treatment modalities are evolving, demanding a more differentiated but pragmatic dissection classification. Our goal was to provide a new practical classification system including Type of dissection, location of the tear of the primary Entry and Malperfusion (TEM). METHODS: We extended the Stanford dissection classification (A and B) by adding non-A non-B aortic dissection, the location of the primary entry tear (E) and malperfusion (M). A 0 was added if the primary entry tear was not visible; 1, if it was in the ascending aorta; 2, if it was in the arch; and 3, if it was in the descending aorta (E0, E1, E2, E3). We added 0 if malperfusion was absent; 1, if coronary arteries; 2, if supra-aortic vessels; and 3, if visceral/renal and/or a lower extremity was affected (M0, M1, M2, M3). Plus (+) was added if malperfusion was clinically present and minus (-) if it was a radiological finding. RESULTS: The new classification system was analysed in 357 patients retrospectively; distribution was 59%, 31% and 10% for A, B and non-A non-B dissections. The in-hospital mortality rate was 16%, 5% and 8% (P = 0.01). Postoperative stroke occurred in 14%, 1% and 3% (P < 0.001). The in-hospital mortality rate was 22%, 14%, 40% and 0% in A E0, E1, E2 and E3 (P = 0.023), respectively. Two years after the onset of dissection, the lowest survival rate was observed in A, followed by non-A non-B and B (83 ± 3% vs 88 ± 6% vs 93 ± 3%; P = 0.019). CONCLUSIONS: The new practical TEM aortic dissection classification system adds clarity regarding the extent of the disease process, enhances awareness of the disease mechanism, aids in decision-making regarding the extent of repair and helps in anticipating outcome.