ABSTRACT Background For the treatment of stenotic lesions developing in dilated coronary arteries, it is difficult to find an appropriately sized coronary stent given that the vessel diameter is too large. This poses a greater problem, especially in patients who require urgent intervention, such as acute coronary syndrome. Objective We aimed to evaluate the efficacy and safety of renal stents implanted in ectatic/aneurysmatic coronary arteries in such patients. Methods In total, 18 patients (renal stent group) who underwent renal stent implantation in ectatic/aneurysmatic coronary arteries requiring percutaneous coronary intervention (PCI) and 45 patients who underwent large-sized bare-metal coronary stent (BMCS) implantation (BMCS group) at our center were included in the study. The primary endpoints were MACE (myocardial infarction and cardiovascular mortality), and the secondary endpoints were restenosis and all-cause mortality. Results In the study patients with a mean follow-up of 25.3 ± 14.6 months (1–48 months), the control coronary angiography duration was 24.6 ± 14.8 months for the renal stent group and 22.8 ± 15.7 months for the BMCS group (p = 0.06). The MACE was observed in 2 (11.1%) patients in the renal stent group and 4 (8.9%) patients in the BMCS group (HR: 1.39 (0.24–7.82), p = 0.70). The secondary composite outcome was identified in 4 (22.2%) patients in the renal stent group and 6 (13.7%) patients in the BMCS group (HR: 1.93 (0.53–6.91), p = 0.31). No significant differences in primary and secondary outcomes were noted between the groups. Conclusion Renal stents used during PCI in patients with acute coronary syndrome with ectatic/aneurysmatic coronary arteries have similar efficacy, and mid-term follow-up results those noted for BMCS. These findings support that renal stents can be used in ectatic and aneurysmatic coronary arteries when necessary. Clinical Trial Registration This study has been registered on ClinicalTrials.gov (NCT05410678).