Background: A tombstoning pattern (T-pattern) is associated with in-hospital poor outcomes patients with ST-segment elevation myocardial infarction (STEMI), but no data are available for midterm follow-up. We sought to determine the prognostic value of a T-pattern on admission electrocardiography (ECG) for in-hospital and midterm mortality in patients with anterior wall STEMI treated with primary percutaneous coronary intervention (PCI). Methods: After exclusion, 169 consecutive patients with anterior wall STEMI (mean age: 55 +/- 12.9 years; 145 men) undergoing primary PCI were prospectively enrolled in this study. Patients were classified as a T-pattern (n = 32) or nonT-pattern (n = 137) based upon the admission ECG. Follow-up to 6 months was performed. Results: In-hospital mortality tended to be higher in the T-pattern group compared with nonT-pattern group (9.3% vs 2.1% respectively, P = 0.05). All-cause mortality was higher in the T-pattern group than nonT-pattern group for 6 month (P = 0.004). After adjusting the baseline characteristics, the T-pattern remained an independent predictor of 6-month all-cause mortality (odds ratio: 5.18; 95% confidence interval: 1.2521.47, P = 0.02). Conclusion: A T-pattern is a strong independent predictor of 6-month all-cause mortality in anterior STEMI treated with primary PCI. Therefore, it may be an indicator of high risk among patients with anterior wall STEMI.