C825T polymorphism in the G protein beta3 subunit gene (GNB3) has been associated with arterial hypertension, coronary artery disease and myocardial infarction. On the cellular level, C825T polymorphism is associated with altered transmembrane signaling via adenylyl cyclase inhibiting (G(i)) G proteins. This study was designed to test whether C825T polymorphism has an impact on the processes leading to restenosis and thrombosis following coronary stenting. The primary endpoint of the study was angiographic restenosis (> or =50% diameter stenosis) at 6-month follow-up. Secondary endpoint was angiographically proven stent thrombosis within 30 days of implantation. In the 562 consecutive patients C825T genotype was CC, 46.1%, CT, 45.2% and TT, 8.7%. The incidence of angiographic restenosis was 32.7% in homozygous carriers of the C allele, 28.2% in CT patients and 33.3% in homozygous carriers of the T allele (P = 0.563). C825T genotype distribution in 34 consecutive patients with subacute stent thrombosis (44.0% CC, 50.0% CT, and 6.0% TT) was not different from that of 451 patients with angiographically patent stented vessel (45.4% CC, 44.6% CT, 10.0% TT; P = 0.644). In conclusion, C825T polymorphism has no appreciable impact on the mechanisms leading to thrombosis and restenosis following coronary stent placement.