An insect-specific toxin from the venom of the scorpion Androctonus australis Hector has been crystallized. The crystals are orthorhombic, space groups P2(1)2(1)2(1), with cell dimensions a = 66.4 A, b = 52.5 A and c = 36.1 A. Calculations based on the unit cell volume and toxin molecular mass suggest that there are two molecules in the asymmetric unit.