Two stocks of large Babesia from dogs originating in France, transmitted by Dermacentor reticulatus, two from North Africa, having Rhipicephalus sanguineus as vector, and one from South Africa, transmitted by Haemaphysalis leachi, were compared in cross-immunity tests in dogs and in the indirect fluorescent antibody test (IFAT). The French and North African stocks did not immunise against the South African one, while the North African stocks did not protect against a French one. The South African stock partially protected against a French one. The three groups could be clearly distinguished in the IFAT. These differences have practical implications for existing and future vaccines against canine babesiosis and for the serological diagnosis of atypical and chronic cases. It is proposed to use a trinomial system of nomenclature for these groups: Babesia canis canis (Piana and Galli-Valerio, 1895), Babesia canis vogeli Reichenow, 1937, and Babesia canis rossi (Nuttall, 1910), having Dermacentor, Rhipicephalus and Haemaphysalis ticks as their vectors respectively.