We previously reported that DNA catalysts (deoxyribozymes) can hydrolyze DNA phosphodiester linkages, but DNA-catalyzed amide bond hydrolysis has been elusive. Here we used in vitro selection to identify DNA catalysts that hydrolyze ester linkages as well as DNA catalysts that hydrolyze aromatic amides, for which the leaving group is an aniline moiety. The aromatic amide-hydrolyzing deoxyribozymes were examined using linear free energy relationship analysis. The hydrolysis reaction is unaffected by substituents on the aromatic ring (rho approximate to 0), suggesting general acid-catalyzed elimination as the likely rate-determining step of the addition-elimination hydrolysis mechanism. These findings establish that DNA has the catalytic ability to achieve hydrolysis of esters and aromatic amides as carbonyl-based substrates, and they suggest a mechanism-based approach to achieve DNA-catalyzed aliphatic amide hydrolysis.