The blood group antigen Dog Erythrocyte Antigen (DEA) 1.1 is clinically the most important canine blood group as DEA 1.1 antibodies are capable of causing acute haemolytic, potentially life-threatening transfusion reactions. Dogs do not have naturally occurring antibodies to DEA 1.1 but are rapidly sensitised by the first incompatible transfusion. The prevalence of DEA 1.1 in the general dog population is estimated at 42-46 %. Canine blood donors registered with the Onderstepoort Animal Blood Bank (n = 93) as well as potential donors (n = 140) were typed for DEA 1.1 using a monoclonal antibody card kit. All dogs came from the Onderstepoort area, near Pretoria, Gauteng province, South Africa. Overall prevalence of DEA 1.1 was 47 %. Prevalence was 47 % in purebred dogs and 48 % in mongrels. Distinct breed differences were noted with less than 20 % of German shepherd dogs and Boxers and greater than 75 % of Rottweilers, Great Danes, St Bernards and Dalmations testing DEA 1.1 positive. Knowledge of local breed differences will increase effectiveness of blood donor recruitment