Abstract: Objective To investigate the effect of depression on the short clinical outcome in patients with ST-elevated myocardial infarction (STEMI) treated with percutaneous coronary intervention. Methods A nested and matched case-control study was performed. Totally 209 patients with STEMI were enrolled and divided into two groups: 72 patients with depression and 137 patients without depression. Major adverse cardiac events (MACE)were observed as the composite end points. MACE was compared between these two groups by the end of a 12-month follow-up after PCI. Results After a 12-month follow-up, the MACE rate of STEMI patients with depression was higher than that of patients without depression. Mortality rate in both groups did not have significant difference. The incidence of malignant arrhythmia was significantly different between the two groups. Conclusion Depression can induce a bad clinical outcome in STEMI patients treated with percutaneous coronary intervention.