Common naturally occurring polymorphisms have been identified in the coding regions of the α 1A -, α 2B -, β 1 - and β 2 -adrenoceptor (AR) genes [α 1A -AR R492C, α 2B -AR insertion/deletion (I/D), β 1 -AR R389G, β 2 -AR G16R and β 2 -AR Q27E] and are associated with modified in vivo and in vitro functionality. We tested their possible effects on the haemodynamic responses to intravenous adrenaline (20, 40, 80 and 160ng/kg of body weight per min; 5min for each infusion rate) before and after β-blockade (propranolol) in 16 young healthy men. We monitored changes in heart rate, blood pressure (BP), ECG, coronary flow velocity and plasma adrenaline and noradrenaline. The Cys/Cys (CC) genotype of the α 1A -AR R492C polymorphism was associated with a longer ECG PR interval before and during the adrenaline infusions. The deletion/deletion (D/D) genotype of the α 2B -AR I/D polymorphism was associated with blunted coronary blood flow increases during the adrenaline infusion before β-blockade. The β 1 -AR R389G polymorphism was not associated with modified responses to infused adrenaline. Subjects carrying the Gly/Gly (GG) genotype of the β 2 -AR G16R polymorphism demonstrated increases in diastolic BP upon adrenaline infusion, whereas diastolic BP was decreased in the other genotype groups. These results suggest that, upon acute adrenaline infusion, the α 2B -AR D/D genotype confers increased vasoconstriction and that the β 2 -AR GG genotype confers reduced vasodilatation.