Dye-decolourizing peroxidases are haem-containing peroxidases with broad substrate specificity. Using H₂O₂as an electron acceptor, they efficiently decolourize various dyes that are of industrial and environmental relevance, such as anthraquninone- and azo-based dyes. In this study, the dye-decolourizing peroxidase DdDyP fromDictyostelium discoideumwas overexpressed inEscherichia colistrain Rosetta(DE3)pLysS, purified and crystallized using the vapour-diffusion method. A native crystal diffracted to 1.65 Å resolution and belonged to space groupP4₁2₁2, with unit-cell parametersa=b= 141.03,c = 95.56 Å, α = β = γ = 90°. The asymmetric unit contains two molecules.