Objective To evaluate the frequency, severity, and clinical implication of the plaque prolapse(PP) after Cypher and TAXUS stent implantation using volumetric intravascular ultrasound(IVUS) analysis. Method We used the POET trial data which is a prospective, multicenter, randomized trial aimed at demonstrating the efficacy of adjuvant balloons in PCI procedure using DESs randomly allocated(SES vs. PES). Serial IVUS analysis was performed for both stent segment encompassing PP at post-procedure and matched location of the site of PP at 8month follow-up. The remaining stented segments without PP(non-PP) were also quantified as above. IVUS parameters at PP site were compared with non-PP site in each time course (post-procedure & follow-up) and also compared between SES and PES. Results PP were discovered at 18 sites (Cypher=5, TAXUS=13, p=ns) in 17 stented segments of 216(8.3%)lesions. Post-procedure average PP area was 0.21mm2 in SES and 0.08mm2 in PES (p=ns). At follow-up, tissue volume increased at PP site was more prominent in TAXUS compared with Cypher (1.25mm2 vs. 0.52mm2) although not statistically significant. Neointimal proliferation was similar between PP and non-PP site in both Cypher and TAXUS (0.51mm2 vs. 0.52mm2 in SES/ 1.23mm2 vs. 1.25mm2 in PES). Restenosis rate and TLR were similar between PP and non-PP lesions. Conclusion The incidence of PP was similar in SES and PES. PP was not associated with exaggerated neointimal proliferation in either SES or PES. PP was not associated with restenosis or TLR.