Peracetic acid (PAA) is useful in treating a wide variety of serious fish diseases in aquaculture. As no information on PAA toxicity to crayfish is available, we conducted acute toxicity tests of Persteril 36, a commercial PAA-containing product, on three age/size classes of signal crayfish, Pacifastacus leniusculus. Results confirmed high tolerance of the target species to this product, expressed as a 96h LC50 of 77.3±1.0mgL−1 PAA in adults and low post-treatment mortality in 9month old juveniles. As PAA concentrations successfully applied in aquaculture are generally 2.0mgL−1 or lower, PAA can be recommended for use in astaciculture. After necessary evaluations, uses might include limiting spread of crayfish plague, treating saprolegniosis on artificially incubated crayfish eggs, and avoiding translocations of further crayfish-related non-native species when introducing crayfish or stocking them in closed culture systems. ► Acute toxicity of Persteril 36 to the signal crayfish was evaluated. ► High tolerance of target crayfish to this PAA-containing product was found. ► Results support widespread use of peracetic acid in crayfish culture. ► Treated diseases might include e.g. crayfish plague and saprolegniosis on eggs.