ObjectivesTo assess the mortality in patients with diabetes mellitus (DM) following percutaneous coronary intervention (PCI) according to their insulin requirement and PCI setting (elective, urgent, and emergency).BackgroundDM is a major risk factor to develop coronary artery disease (CAD). It is unclear if meticulous glycemic control and aggressive risk factor management in patients with DM has improved outcomes following PCI.MethodsRetrospective analysis of prospectively collected data on 9,224 patients treated with PCI at a regional tertiary center between 2008 and 2011.ResultsAbout 7,652 patients were nondiabetics (non‐DM), 1,116 had non‐insulin treated diabetes mellitus (NITDM) and 456 had ITDM. Multi‐vessel coronary artery disease, renal impairment and non‐coronary vascular disease were more prevalent in DM patients. Overall 30‐day mortality rate was 2.4%. In a logistic regression model, the adjusted odds ratios (95% confidence intervals [CI]) for 30‐day mortality were 1.28 (0.81–2.03, P = 0.34) in NITDM and 2.82 (1.61–4.94, P < 0.001) in ITDM compared with non‐DM. During a median follow‐up period of 641 days, longer‐term post‐30 day mortality rate was 5.3%. In the Cox's proportional hazard model, the hazard ratios (95% CI) for longer‐term mortality were 1.15 (0.88–1.49, P = 0.31) in NITDM and 1.88 (1.38–2.55, P < 0.001) in ITDM compared with non‐DM group. Similar result was observed in all three different PCI settings.ConclusionIn the modern era of aggressive cardiovascular risk factor control in diabetes, this study reveals higher mortality only in insulin‐treated diabetic patients following PCI for stable coronary artery disease and acute coronary syndrome. Importantly, diabetic patients with good risk factor control and managed on diet or oral hypoglycemics have similar outcomes to the non‐diabetic population. © 2016 The Authors Catheterization and Cardiovascular Interventions Published by Wiley Periodicals, Inc.