In this study, a simple one-pot synthesis of acetamides from aromatic amines and acetonitrile in the presence of H2O and K2S2O8 is presented. The reaction proceeds in a mixed solvent (CH3CN: DMSO, 3:1) without using metals or toxic reagents. Various N-acetanilides are obtained with 53-91% yields. The method is selective for aromatic amines, with aliphatic amines remaining intact. This represents a new, efficient, and economical method for the synthesis of a range of acetamides.