Canine leishmaniosis is a severe systemic disease caused by the kinetoplastid protozoan Leishmania infantum, an obligatory intracellular parasite of mammalian macrophages, transmitted by the bite of phlebotomine sandflies. The infection in dogs might occur without any clinical signs or might be characterised by chronic viscerocutaneous signs, such as lymphadenopathy, skin lesions, splenomegaly, onychogryphosis, and renal as well as ocular damage due to immunocomplex deposition. In atypical cases the parasites can be found in the striated musculature, the central nervous system, the endocrine glands or gonads, with or without functional damage. Leishmania infection might seldom induce oral lesions, particularly on the tongue. The authors describe the clinical case of a four-year old mongrel dog with tongue lesions caused by L. infantum. The dog was presented due to diarrhoea, lack of appetite and hypersalivation. Examination of the oral cavity revealed the presence of multiple red, nodular lesions on the dorsal and lateral surfaces of the tongue. Definite diagnosis of an infection with L. infantum was obtained by an indirect immunofluorescence antibody test (IFAT) and by the cytological identification of the parasite in nodular, lingual lesions and bone marrow aspirates. The dog was treated with a combination of miltefosine (Milteforan®, Virbac), 2 mg/kg orally once a day for four weeks and allopurinol (Ziloric®, GlaxoSmithKline), 10 mg/kg orally twice a day for six months. At the end of the treatment, the animal showed full remission of clinical signs. The authors outline the atypical manifestations in the oral cavity in combination with a L. infantum infection and discuss the therapeutic potential of the combination treatment of miltefosine and allopurinol in canine leishmaniosis.