Angiostrongylosis was diagnosed in 23 dogs presenting Queen Mother Hospital for Animals between June 1999 and 2002. The animals' clinical records were reviewed retrospectively and certain risk factors were compared with a control population of 3407 dogs. Twenty-two of the 23 dogs were from south-England and dogs from Surrey (n=8) were significantly overrepresented. There were also significantly more Cavalier Charles spaniels (n=5) and Staffordshire bull terriers (n=the affected dogs than in the control group. The median affected dogs was 10 months (range five to 90 months). common presenting signs were cough (65 per cent), dyspnoea (43 per cent), haemorrhagic diathesis (35 per cent) and (26 per cent). Four dogs were thrombocytopenic and eight significant prolongations in prothrombin time and/or activated partial thromboplastin time. Thoracic radiographs were abnormal 18 of 19 dogs. A variety of changes were observed, the most being a patchy alveolar-interstitial pattern affecting the dorsocaudal lung fields. Angiostrongylus vasorum larvae were found in 10 bronchoalveolar lavage specimens and 19 of 19 faecal Three dogs died shortly after admission to the hospital. The remainder were successfully treated with fenbendazole at of 50 mg/kg for five to 21 days. A vasorum should now be considered endemic to south-east England.