BACKGROUND This study aimed to assess the association between left-behind status and the prognosis of ST-elevation myocardial infarction (STEMI). MATERIAL AND METHODS A total of 1 015 patients with STEMI patients from 4 tertiary medical centers in southwest China were enrolled and categorized into left-behind and not-left-behind groups. The primary endpoints were major adverse cardiovascular and cerebrovascular events (MACCEs), which were assessed with Kaplan-Meier curves. Multivariate Cox regression analyses were used to explore the predictive value of left-behind status for MACCEs. RESULTS Patients in the left-behind group were older than those in the not-left-behind group (70 vs. 65 years, P<0.001). The patients in the left-behind group had a lower incidence of history of coronary heart disease and diabetes mellitus than those in the not-left-behind group. Meanwhile, the left-behind group had higher levels of alanine aminotransferase (42 vs. 31, P<0.001), low-density lipoprotein cholesterol concentration (2.64 vs. 2.62, P=0.001) and cardiac troponin I (5.11 vs. 2.84, P=0.001) than the not-left-behind group. During the 18-month follow-up, the left-behind group experienced a higher rate of adverse events than the not-left-behind group (123/26.2% vs. 81/14.8%, P<0.001). After multivariate adjustment, the left-behind group also had a 1.778-fold (95% CI: 1.241-2.547, P=0.002) higher risk of experiencing MACCEs than the not-left-behind group. CONCLUSIONS Left-behind status is an independent predictor of STEMI prognosis.