Ehrlichia canis, the etiologic agent of canine monocytic ehrlichiosis (CME), is mainly transmitted by the brown dog tick Rhipicephalus sanguineus. Clinical signs of the disease can be various, depending on the stage of the disease. Typical changes in hematological and blood biochemical parameters are: severe thrombocytopenia, mild to marked non regenerative anaemia and hypoalbuminemia. In order to present the effects of the treatment protocol on several hematological and biochemistry parameters, 34 Ehrlichia canis positive dogs were compared before and after treatment with doxycycline 10mg/kg/day, in duration of four weeks. Besides the clinical sings and laboratory findings, diagnosis was confirmed by antibody tests (Bionote, Korea, AGROLABO S.p.A., Italy). The most common clinical sings were depression, lethargy, pyrexia, vomiting and anorexia. Hematological analyses were performed on the automatic hematology analyzer Exigo EosVet (Sweden), while biochemistry analyses (alanine aminotransferase, aspartate aminotransferase, urea, creatinine, albumin, total protein, globulin and alkaline phosphatase) were performed using the automatic analyzer ChemWell 2910 (Awareness Technology, INC, USA). Statistically significant difference (p<0.05) in hematology changes was present regarding the red blood cells count, platelet count, hematocrit and hemoglobin before and after treatment. Hypoalbuminaemia (Mean 19.21 ±4.96 g/l) was the only serum biochemistry parameter with significant change before and after treatment, as well. Treatment with doxycycline in patients with E.canis resulted in significant increase of hematology parameters (red blood cells, hemoglobin, haematocrit and platelets), as well as albumins in serum.