Abstract The morphological composition, the level of thyroxine and cortisol in the blood and the crystallogram of blood serum in 36 service Belgian shepherd dogs (malinois) of specialized military kennels of Russia were studied. The tendencies of changes in the blood formula depending on age, season, gender, category of use were identified. In a physiologically mature age, malinois has a higher platelet count, hemoglobin. In repair (training) animals older than two years, the leukogram and crystallogram are more stable, regardless of the season, while the correlation with the hormones thyroxine and cortisol is higher in younger animals. Belgian shepherd dogs in service categories have a tense adaptive status according to the Garkavi stress reactivity index. Significantly fewer monocytes and more lymphocytes in the raspberry mine search service, which corresponds to the reactivation reaction. According to the morphological picture of crystallograms in service malinois, a depressive and reactive state prevails. It is recommended to select malinois for official use more carefully.