The preparation of a series of 1-glutarylindoline-2(S)-carboxylic acid derivatives, 6a-v and 21a-c, is described. The above compounds were tested for inhibition of angiotensin converting enzyme. The structure-activity relationship of the series is also discussed. Compound 6u, the most potent member of the series, had an in vitro IC50 of 4.8 X 10(-9) M. Compound 6v, an ethyl ester of 6u, lowered blood pressure 70 mm in spontaneous hypertensive rats at an oral dose of 30 mg/kg.