Antimicrobial activity of protein hydrolysates from Argentine croaker (Umbrina canosai) with different degrees of hydrolysis (DH: 10–20%) prepared using Protamex were determined. The proteins were recovered from Argentine croaker by washing process (CMP). Results showed that an increase in the DH resulted in higher content of hydrophobic and aromatic amino acids and in a decrease in molecular weight (MW) distribution for hydrolysates obtained. In all the evaluated microorganisms, only Gram-positive was inhibited, The hydrolysate with DH 20% is effective antibacterial may be used to control the undesirable bacteria in food and improve its safety.