A series of 25 aryloxypropanolamines containing the 3-indolyl-tert-butyl [i.e., 1,1-dimethyl-2-(1H-indol-3-yl)ethyl] or substituted 3-indolyl-tert-butyl moiety as the N substituent is reported. These compounds have been tested for antihypertensive activity in spontaneously hypertensive rats (SHR), beta-adrenergic receptor antagonist action in conscious normotensive rats, vasodilating activity in ganglion-blocked rats with blood pressure maintained by angiotensin II infusion, and for intrinsic sympathomimetic action (ISA) in reserpinized rats. Some of the compounds exhibit antihypertensive activity in combination with beta adrenergic receptor antagonist and vasodilating action. The structure--activity relationships in these tests are discussed.