We have identified thirteen breeds that are registered in the Norwegian Canine Cancer Register with more than five cases of newly diagnosed, primary vascular neoplasia in the period from 1990 to 1998. Incidence rates have been estimated for the boxer and the Bernese mountain dog because the population at risk is known as a result of the 1992/93-census of the Bernese mountain dog, boxer and bichon frisé. The boxer had a mean annual incidence rate for all types of vascular tumours, for both sexes, of 4.3 cases per 1000 dogs. The sex ratio was close to one, and the age group of highest risk was 10-12 years. For vascular cancer, the mean annual incidence rate for both sexes was 1.5 cases per 1000 dogs, and the age group of highest risk was 10-12 years. The mean annual incidence rate of vascular tumours for the Bernese mountain dog for both sexes was 2.5 cases per 1000 dogs. The male to female incidence ratio was approximately 1/2. The age group of highest incidence rate was 10-11 years for all types of vascular tumours as for the vascular cancer. The mean annual incidence rate for malignant tumours for both sexes was 1.0 cases per year per 1000 dogs. For all thirteen breeds, the relative risk of all types of vascular tumours has been computed ad modum Arnesen. The highest estimated incidence rate of malignant vascular tumours per 1000 dogs was found in the boxer (1.5). The flat-coated retriever and Bernese mountain dog had 1.0 and 0.9, respectively, and the German shepherd had 0.8. The study shows that the German shepherd is not the breed with the highest frequency of vascular tumour when the population at risk is taken into consideration, although the total number of vascular tumours is highest in this breed.