Leptospirosis is a bacterial disease affecting several mammalian species, including human beings. In dogs, it is spread mainly by rodents that act as a maintenance host for several Leptospira serovars. Until recently, the most common signs observed in affected dogs consisted of icterus and haemorrhagic diathesis, but today the most prevalent clinical signs are attributed to acute renal failure. The current literature gives a good review of leptospirosis in dogs in the usa and Canada, but less information is available about its occurrence in Europe. This review considers the clinical signs, diagnosis, treatment and prevention of this emerging zoonotic disease.