Abstract Objectives We sought to compare outcomes between patients with acute myocardial infarction (AMI) undergoing percutaneous transluminal coronary angioplasty (PTCA) with an optimal or “stent-like” result versus patients who underwent routine stent placement. Background Recent studies in patients with AMI undergoing stent implantation have suggested that PTCA may no longer be a relevant treatment modality for stent eligible lesions. However, whether routine stent placement is superior or necessary when an optimal PTCA or “stent-like” result is achieved is unknown. Methods In the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial, 2,082 patients with AMI were randomly assigned to undergo PTCA alone, PTCA + abciximab, stenting alone, or stenting + abciximab. Outcomes were compared in patients achieving an optimal acute PTCA result (residual core laboratory diameter stenosis <30% without significant dissection) versus those assigned to routine stenting. Results Optimal PTCA was achieved in 40.7% of patients randomized to balloon angioplasty, including 38.5% and 42.7% assigned to PTCA alone and PTCA + abciximab, respectively. Ischemic target vessel revascularization (TVR) at 30 days occurred more frequently after optimal PTCA than routine stenting (5.1% vs. 2.3%, p = 0.007). The one-year composite adverse event rate (death, reinfarction, disabling stroke, or TVR) was greater after optimal PTCA than routine stenting (21.9% vs. 13.8%, p < 0.001), driven largely by increased rates of ischemic TVR (19.1% vs. 9.1%, p < 0.001); no significant differences were present in the rates of death, reinfarction, or disabling stroke between the two groups. Angiographic restenosis also was more common with optimal PTCA than routine stenting (36.2% vs. 22.2%, p = 0.003). Even a post-PTCA diameter stenosis of <20% (realized in 12% of patients) did not result in outcomes equivalent to stenting. Conclusions Even if an optimal result is achieved after primary PTCA in AMI, early and late outcomes can be further improved with routine stent implantation.