Canine leishmaniosis (CL) has become one of the most frequently diagnosed travel associated infection in dogs in Switzerland and Germany. The aim of the study was to define recommendations for treatment with allopurinol and follow-up examinations of dogs with CL in a non endemic area. 31 dogs infected with Leishmania were treated with allopurinol (10 - 15 mg/kg twice daily, per os) and the effectiveness was examined. The diagnosis had been confirmed by the detection of specific anti-Leishmania antibodies and/or Leihmania-DNA. 22 dogs had clinical signs (skin lesions, lameness or lack of fitness) and 9 dogs were asymptomatic but showed abnormal laboratory parameters. Under treatment with allopurinol the symptoms disappeared within 1 - 5 months in 20 dogs.