Hydrolysis of various nitriles to amides was carried out in aqueous phase over suspended copper catalysts. Cross-linked poly(4-vinylpyridine), magnesia, and silica-magnesia were used as supports. Copper-on-polymer was highly active in comparison with copper powder. In spite of the larger crystallite size, copper-on-magnesia (68 Å) was much more active than copper-on-polymer (amorphous) for selective hydrolysis of nicotinonitrile to amide. A cooperative effect of copper and the basic support was suggested. However, weakly acidic silica-magnesia was favorable as support than basic magnesia for hydrolysis of aliphatic nitriles to amides. Selectivity to acrylamide over copper-on-magnesia was as high as 75%, which would be difficult to attain by the alkaline hydrolysis, but the side reaction to cyanohydrin (8%) was not negligible. Copper-on-silicamagnesia resulted in the predominant formation of acrylamide. An 88% conversion of acrylonitrile was obtained in 8 hr at 80 °C with selectivities of 97% to amide and 0.8% to cyanohydrin. Results for propionitrile and benzonitrile are also described. The present catalysts were shown to degenerate on exposure to air. Hydrogen reduction was effective for complete regeneration of the deactivated copper-on-silica-magnesia, while it was unsuccessful for copper-on-polymer. The rate of hydrolysis revealed to deviate from first order kinetics at higher conversions. The kinetic behavior was explained by the product retardation.