Cytolytic toxins produced by Aeromonas hydrophila and Aeromonas veronii biotype sobria strains were partially purified from culture filtrates by two steps of purification: ammonium sulfate precipitation and hydrophobic chromatography using Phenyl-Sepharose CL-4B. Hemolytic activity was detected in one or two peaks in elution profile. Purified toxins were also cytotoxic to Vero and CHO cells. Moreover, these toxins revealed cytotonic activity to CHO cells.