Ethanolamine derivatives and their acid addition salts are prepared (1) by reacting a 1-(3,4-methylenedioxyphenyl)-2-aminoethanol compound or an .alpha.-amino-(3,4-methylenedioxy)acetophenone compound with an alkanal or an alkanone under reduction conditions, (2) by hydrogenating and/or hydrogenolyzing a 1-(3,4-methylenedioxyphenyl)-2-(N-substituted amino)-ethanol compound or an .alpha.-(N-substituted amino)-(3,4-methylenedioxy)acetophenone compound, and (3) by reacting a (3,4-methylenedioxyphenyl)-ethylene oxide compound or a 1-(3,4-methylenedioxyphenyl)-2-substituted ethanol compound with an amine. The ethanolamine derivatives and their salts show .beta.-adrenergic receptor blocking activity, and are expected to be useful in the treatment of heart disease, hypertension, myocardites and pheochromocytoma.