The phospholipases A2 (PLA2, E.C. 3.1.1.4, phosphatide sn2 acylhydrolases) are the major components of the venom of several snakes. They are responsible for several important pharmacological effects observed in ophidian incidents. PLA2 piratoxin II from Bothrops pirajai has been crystallized by the vapour-diffusion technique. X-ray diffraction data have been collected to 2.04 A resolution (90.2% complete, Rmerge = 0.070). The space group is P21 and the cell parameters are a = 46.19, b = 60.36, c = 58.74 A and beta = 96.05 degrees. The structure has been solved by molecular replacement using the crystallographic structure of PLA2 from Bothrops asper (PDB code 1CLP) as a search model.