The morphological similarity between species of the rock scorpion genus Hadogenes has given rise to a great deal of controversy amongst taxonomists over the last eighty years. To resolve these difficulties, species of the genus were re-appraised in terms of their chromosome number and an electrophoretic analysis of venom proteins. The relationships arising from these data were integrated with morphological characteristics in order to get a more realistic appreciation of the genus. It emerges that the genus consists of 14 recognised species, some of which represent as yet unnamed species complexes. Taxonomic changes proposed are H. lawrencei sp. res., H. zuluanus stat. nov, H. gracilis fluvianus and H. gracilis namaquensis = H. phyllodes syn. n. A new key to the species is provided.