Canine histiocytoma is regarded as a benign neoplasm and seen mostly in dogs younger than 2 years of age. Multiple histiocytomas rarely occur and most frequently seen in Shar Peis. Histiocytomas usually undergo spontaneous regression, and recurrence is very rare. The aim of this case report is to present the recovering of young dog with multiple histiocytoma by treatment with lomustine. A 1-year-old, Rottweiler, neutered female dog was presented to the clinic with complaints of multiple cutaneous lesions, high fever, lethargy and anorexia. The lesions had been present for 2 months and they were subcutaneous, progressive, ulcerative, erythematous and button-like multiple masses ranged between 0.5 to 2 cm in diameter. Skin biopsy specimens were obtained from the right hindlimb for histopathological examination. The preparation of the specimens were performed through routine Hematoxylin and Eosin staining and also immunohistochemistry. Histopathology revealed non-encapsulated, densely cellular composition of histiocytic cells, which were arranged in sheets. There was also severe inflammation characterized by neutrophil leukocyte infiltration. The case was diagnosed as multiple histiocytoma. Although the improvement had been obtained by treatment with corticosteroids, recurrence of the lesions was observed as the dose of the corticosteroids was tried to be reduced. However, no recurrence has been observed during the treatment with lomustine for 3 months. As a result; the use of lomustine in this case was found to be successful in the treatment of multiple cutaneous histiocytomas, as previously mentioned.