We discuss two cases of non-occlusive sub-acute/late stent thrombosis, one correctly diagnosed (with the help of intravascular ultrasound) 12 days after implantation of a sirolimus eluting stent, the other erroneously non recognized 17 days after implantation of a bare metal stent and evolving 6 weeks later in total thrombotic occlusion of the stent itself. We believe that our clinical judgment, accurate in case of sirolimus eluting stent thrombosis, but wrong in case of bare metal stent thrombosis, was largely influenced by the recent literature giving overwhelming attention, in the drug-eluting stent era, to an issue (late stent thrombosis) that was already present but under-considered, also in the bare metal stent era.