Leihsmaniasis is a protozoal disease transmitted by dipteran insects. The dog is an important domestic host of both visceral and cutaneous forms of the disease. These forms affects humans in many countries, and it is considered a serious risk for human health. This study reports clinical and laboratorial data from 18 dogs. Nine dogs were positive by indirect immunofluorescence technique and the other nine were negative. The dogs were clinically monitored for 30 days and laboratorial changes were assessed. Three blood samples were collected for hemogram and serum biochemistry at 0, 15, and 30 days. The clinical signs of positive dogs were compatible with the disease, including lymphadenopathy, cutaneous ulcers, hyperthermia, apathy, cachexia and ulcerated mucosa. Marked differences were observed in the blood cell counts and blood biochemistry between positive and negative dogs. In conclusion, blood and biochemistry analyses of positive dogs were not sufficient to diagnose the disease within the period studied. The serologic test associated with the clinical signs are important to confirm the diagnosis.