Novel phenylethanolamine derivatives represented by the formula ##STR1## wherein R represents a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkyl group, a lower alkoxy group, a lower alkylthio group, an amino group, a lower acylamino group, a lower alkylsulfonyl group, or a lower alkylsulfonylamino group; R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be the same or different, each represents hydrogen or a lower alkyl group; R.sub.5 represents an aryl group which may have a substituent, a benzodioxane ring group which may have a substituent, an aryloxy group which may have a substituent, or an arylthio group which may have a substituent; said R.sub.5 being, however, a benzodioxane ring group which may have a substituent, an aryloxy group which may have a substituent, or an arylthio group which may have a substituent when R is a hydroxyl group; and n represents 0 or an integer of 1-3 and the acid addition salts thereof.The compounds of this invention exhibit .alpha.- and .beta.-adrenergic blocking actions and are useful as antihypertensive agents.