Background: The advent of drug-eluting stents (DES) has raised concerns regarding later occurring stent thrombosis (ST). Little is known about occurrence of ST more than 1 year after stent implantation. Methods: We assessed clinical and procedural data from 17 patients with angiographically documented stent thrombosis which developed at least 1 year after stent implantation. Results: The mean time to occurrence of very late ST was 822 days (range, 379 to 1340 days). The majority of patients (82.4%) were initially presented with an acute coronary syndrome. The number of stents was 1.71 (range, 1 to 3) and total stent length was 45.6 mm (range, 23 to 90 mm). Absence of anti-platelet treatment was noted in 7 (41.2%) patients and average duration of drug discontinuation was 3.2 days (range, 2-5 days). Stent fracture was associated with ST in 2 (11.8%) patients. The majority of patients (88.2%) who presented with ST developed myocardial infarction. Percutaneous coronary intervention was the initial treatment strategy in all patients. None developed cardiac death during one month following ST. Conclusions: Very late ST with DES, which can unpredictably occur at any time point, might be attributed to clinical factor such as anti-platelet discontinuation.