Coronary angioscopy can directly visualize luminal morphology and stent architecture. This new technology may provide insights into the stent mechanism of action and help guide stent procedures. Visualization of the target vessel segment with a 4.5Fr angioscope was attempted before and/or after Palmaz-Schatz coronary stent implantation in 50 patients. The target vessel segment was successfully visualized in 48 patients (96%). In 24 patients, angioscopy was performed both after balloon angioplasty and then again after stenting. In 16 of these 24 patients a dissection was documented by angioscopy after balloon angioplasty, and in each patient the dissection was absent after stenting. Angioscopy influenced the clinical management of 18 (37.5%) patients. Clinical decisions directly influenced by angioscopy included intracoronary thrombolytic therapy for thrombus visualized angioscopically, which had been unsuspected by angiography (n = 7), withholding intracoronary thrombolytic therapy for patients with suspected thrombus not confirmed by angioscopy (n = 4), repeat angioplasty in patients in whom plaque was found to be bulging into the lumen at the stent articulation site (n = 4), additional stents placed when angioscopy revealed significant proximal or distal disease (n = 4), or an unsuspected gap between 2 tandem stents (n = 1). Coronary angioscopy safely visualized stented vessel segments in most patients. Angioscopic observations provided insights into the stent mechanism of action and, in some cases, influenced clinical management.