Abstract Background The time from symptom onset to reperfusion therapy was particularly important for ST-segment elevation myocardial infarction (STEMI) patients. We sought to investigate the impact of social factors on prompt reperfusion in STEMI patients. Methods A total of 5,264 patients with a diagnosis of STEMI from Korean Registry of Acute Myocardial Infarction (KRAMI) was participated in present study. The association between social factors and process of symptom onset-to-timely reperfusion was evaluated. Process of symptom-to-reperfusion time was included door-to-balloon (DTB) time, symptom-to-door (STD) time and symptom-to-balloon (STB) time. Results In the entire study population, the median times of DTB, STD and STB were 55 min, 117 min and 175 min, respectively. With 3 parameters, only DTB was associated with in-hospital mortality (Fig. 1 and 2). Old age and male were more likely to delay treatment (p for age=0.000; p for gender <0.0001). Moreover, higher education was linked to reduction of STD and STB time (p<0.05). Living alone was associated with prolonged STB time, and symptom appearing outside was linked to delay medical care. Transportation with ambulance was significantly associated with reduction of reperfusion time, and inter-hospital transportation was particularly prominent (STD: OR 5.450, 95% CI 4.796 - 6.193, p<0.0001; STB: OR 4.593, 95% CI 4.038 - 5.225, p<0.0001). In addition, treatment time during off-hours was relatively delayed DTB time. Conclusions Door to balloon time is directy related to in-hospital mortality. Social factors, such as age, gender, and education level, and transportation with ambulance were related to timely reperfusion in STEMI patients.