Hydrolysis of amide bonds is expected as a promising technology, namely in the fields of biorefinery using proteins and chemical recycling of plastics. For the model reaction of glycylglycine hydrolysis, ZrO2 was found to work as an effective catalyst and afforded glycine in up to 97%-C under the optimum conditions, while acidic oxides and basic oxides were inferior to ZrO2. The characterization using N2 physisorption, XRD, NH3-TPD, and CO2-TPD revealed that the weight-basis activity of ZrO2 correlated with its acidic and basic properties. ZrO2 was demonstrated to be applicable to the hydrolysis of amide bonds: dipeptides with acidic and/or basic side chain(s) into amino acids; small organic amides into both amines and carboxylic acids with their equivalent amounts; and nylon 6 into ε-caprolactam and ε-aminocaproic acid.