AbstractA 16‐year‐old intact female Miniature Dachshund (dog 1) and a 13‐year‐old intact female American Cocker Spaniel (dog 2) presented with a chief complaint of bleeding from a mammary gland tumour ulceration. Dog 1 was transferred to hospital from a local hospital in a haemorrhagic shock state with uncontrolled continuous bleeding. Thoracic radiographs revealed multiple nodular shadows suspected to be pulmonary metastasis. Dog 2 presented with intermittent bleeding from a mass lesion in the right fifth mammary gland. Due to high anaesthetic risk secondary to severe mitral valve insufficiency (ASA status III), the owner declined surgical excision of the tumour. Therefore, microwave ablation (MWA) under local anaesthesia was chosen in order to achieve adequate haemostasis. Both dogs received local anaesthesia around the bleeding mass lesion, and the disintegrated site was microwave‐ablated; dog 1 underwent MWA after blood transfusion to improve the haemorrhagic shock. The ablation site was protected using a non‐adhesive dressing. Scarring of the ulcerated site led to complete haemostasis in both cases. Dog 1 underwent tumorectomy on the 31st hospital day to prevent rebleeding; histopathology results were consistent with mammary adenocarcinoma with the ablation site covered by a capsule structure. To the authors’ knowledge, this is the first case report describing the use of MWA to stop bleeding from mammary tumours in veterinary medicine. MWA is a feasible and potentially effective palliative treatment modality to stop bleeding from disintegrated mammary tumours in dogs under local anaesthesia.