The tetrameric KM+ lectin from the seeds of Artocarpus integrifolia has, when compared to other plant lectins, the singular property of directly inducing neutrophil migration into the peritoneal cavity or into the air pouch of rats. This protein crystals have been grown and they belong to the orthorhombic system with space group C222(1). The unit cell parameters are a = 54.4 A, b = 127.9 A and c = 99.8 A. A native diffraction dataset to 2.8 A was collected and an analysis of the self-rotation function has shown the presence of only one independent non-crystallographic 2-fold axis orthogonal to the crystal b-axis, compatible with a dimer in the asymmetric unit.