Background Recently, several randomized trials have noted improved outcomes with staged percutaneous coronary intervention (PCI) of nonculprit vessels in patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease. However, it remains unclear whether diabetes status affects the outcomes after different revascularization strategies. This study thus compared the impact of diabetes status on long-term outcomes after staged complete revascularization with that after culprit-only PCI. Methods From January 2006 to December 2015, 371 diabetic patients (staged PCI: 164, culprit-only PCI: 207) and 834 nondiabetic patients (staged PCI: 412, culprit-only PCI: 422) with STEMI and multivessel disease were enrolled. The primary endpoint was 5-year major adverse cardiac and cerebrovascular event (MACCE), defined as a composite of all-cause death, myocardial infarction (MI), stroke or unplanned revascularization. Results The rate of the 5-year composite primary endpoint for diabetic patients was close to that for nondiabetic patients (34.5% vs. 33.7%; adjusted hazard ratio [HR] 1.012, 95% confidence interval [CI] 0.815-1.255). In nondiabetic patients, the 5-year risks of MACCE (31.8% vs. 35.5%; adjusted HR 0.638, 95% CI 0.500-0.816), MI (4.6% vs. 9.2%; adjusted HR 0.358, 95% CI 0.200-0.641), unplanned revascularization (19.9% vs. 24.9%; adjusted HR 0.532, 95% CI 0.393-0.720), and the composite of cardiac death, MI or stroke (11.4% vs. 15.2%; adjusted HR 0.621, 95% CI 0.419-0.921) were significantly lower after staged PCI than after culprit-only PCI. In contrast, no significant difference was found between the two groups with respect to MACCE, MI, unplanned revascularization, and the composite of cardiac death, MI or stroke in diabetic patients. Significant interactions were found between diabetes status and revascularization assignment for the composite of cardiac death, MI or stroke (P-interaction = 0.013), MI (P-interaction = 0.005), and unplanned revascularization (P-interaction = 0.013) at 5 years. In addition, the interaction tended to be significant for the primary endpoint of MACCE (P-interaction = 0.053). Moreover, the results of propensity score-matching analysis were concordant with the overall analysis in both diabetic and nondiabetic population. Conclusions In patients with STEMI and multivessel disease, diabetes is not an independent predictor of adverse cardiovascular events at 5 years. In nondiabetic patients, an approach of staged complete revascularization is superior to culprit-only PCI, whereas the advantage of staged PCI is attenuated in diabetic patients. Trial registration This study was not registered in an open access database