This study has investigated the catecholamine involvement in the fibrinolytic modulation of cultured bovine aortic endothelial cells (BAEC). Adrenaline and isoproterenol, at concentrations ranging from 10 to 100 μM, were unable to modulate the fibrinolytic response of these cells. β-Adrenergic binding studies using 3H-CGP 12177 as radioligand evidenced the presence of about 23,113 ± 2,065 sites/cell, with a KD of 1.23 ± 0.29 nM. Isoproterenol stimulated cAMP accumulation at concentrations ranging from 1 to 100 μM, with a maximal accumulation of 30 pmol/106 cell. Hence, in our experimental conditions BAEC, although possessing functional β-adrenergic receptors, were unable to increase any fibrinolytic activity in response to catecholamines.