This invention provides aminomethylene oxindole compounds represented by the formula ##STR1## wherein R is H or loweralkyl; R' is loweralkyl, aralkyl, or R and R' taken together form a chain of the formula --CH.sub.2 CH.sub.2 XCH.sub.2 CH.sub.2 -- wherein X is CH.sub.2 or NR" where R" is loweralkyl, loweralkanoyl, aroyl, alkoxycarbonyl or aryl; and the pharmaceutically acceptable acid addition salts thereof. The compounds of this invention are useful as antihypertensive agents.