Compounds characterized generally as 1,4-thiomorpholinyl-terminated alkylamino ethynyl alanine amino diol derivatives are useful as renin inhibitors for the treatment of hypertension. Compounds of particular interest are those of Formula I ##STR1## wherein A is selected from CO and SO.sub.2 ; wherein X is selected from oxygen atom and methylene; wherein B is a 1,4-thiomorpholinyl group; wherein R.sub.1 is selected from hydrido, methyl, ethyl, isopropyl and n-propyl; wherein R.sub.2 is phenylmethyl; wherein each of R.sub.3 and R.sub.5 is hydrido; wherein R.sub.4 is selected from ##STR2## wherein V is selected from hydrido and methyl; wherein R.sub.6 is cyclohexylmethyl; wherein R.sub.7 is selected from isobutyl, cyclopropyl and cyclopropylmethyl; wherein q is a number selected from zero through three, inclusive; and wherein n is a number selected from zero through three, inclusive; or a pharmaceutically-acceptable salt thereof.