The behavior ofN-benzoylaspartic acid andN-benzoylglutamic acid has been investigated at 100° in dilute solution in water and aqueous hydrochloric acid within the pH range 3.1–0.5. Some data are presented concerning the hydrolysis of theN-benzoyl derivatives of alanine, β-alanine, leucine, glycine, serine, and β-ethanolamine in water, 0.1 Nhydrochloric acid, and 2 Nhydrochloric acid. Benzoylglutamic acid undergoes a pH-independent conversion into pyrrolid-2-one-5-carboxylic acid, which then hydrolyses in mineral acid to glutamic acid; however,N-benzoylaspartic acid, under similar conditions, hydrolyses much more rapidly by a route which does not involve the corresponding lactam as an intermediate. In anhydrous alcohols the solvolysis ofN-benzoylaspartic acid gives mixtures of aspartic acid and the β ester.First-order rate constants have been obtained for the acid-catalyzed hydrolysis of pyrrolid-2-one-5-carboxylic acid (I) and azetidin-2-one-4-carboxylic acid (II) in water over this pH range.