Abstract: Para-substituted phenoxy-hydroxypropylamines having the general formula ##STR1## and pharmaceutically acceptable, non-toxic acid addition salts thereof, wherein R' is an isopropyl or tertiarybutyl radical; Z is a member selected from the group consisting of -OR", -SR", and -NHCOOR", R" being a straight or branched lower alkyl radical having 1 to 3 carbon atoms; and n is 1, 2, or 3, are disclosed as are methods for their preparation. Pharmaceutical preparations are prepared whose active ingredients include at least one of the newly discovered phenoxy-hydroxypropylamine compounds. Therapeutically effective doses of these preparations selectively block the .beta.-receptors of the heart making them useful in treating heart diseases in animals including humans.