Canine dermal haemangiosarcoma (HSA) is believed to have a better prognosis compared to HSA in other organs, but outcome has only been reported in a small number of dogs. The purpose of this study was to assess outcome and prognostic factors in a larger cohort of dogs with dermal HSA. Clinical data was collected retrospectively for 94 dogs and histopathology was reviewed in 53 dogs. Median overall survival time was 987 days. Dogs of predisposed breed with ventral location and histologic solar changes had longer survivals. Loco-regional recurrence occurred in 72/94 (77%) dogs. Predisposed breeds with ventral location and multiple masses were more likely to develop recurrence. Non-predisposed breeds with invasive tumours were more likely to develop metastasis. Results suggest that dogs with solar-induced dermal HSA may have high recurrence rates, but prolonged survivals. Dogs with non-solar tumours may be at increased risk for metastasis and shorter survival.