Due to the scarcity of information on Breton horses, the objective was to study hematobiochemical values of this breed. Blood samples were collected from 29 Bretons, males and females, of different ages, in Brasília-DF, distributed into groups, according to age, without distinction of sex (G1): animals from 4 to 9 years old (n=16) and (G2): from 10 to 26 years old (n=13). The horses were also distributed into males and females for comparisons between the sexes. Values for red blood cells, hemoglobin, creatinine, and urea were statistically higher in females. Fibrinogen was higher in males. Lymphocyte values were higher in G1, but mean corpuscular volume, monocytes, neutrophils, and GGT in G2 were higher than G1. The hematocrit value differed between the ages of the females and was higher than that of the males, while the older male animals showed higher values than the young animals. Females presented lower platelet values than males, with older females having higher platelet values than younger females, in the same way as males. G1 females had the highest leukocyte values. The leukocyte values in males of G2 were higher than those of G1. This same behavior occurred for lymphocytes, eosinophils, and creatine kinase. Considering the albumin and aspartate aminotransferase variables, females had the highest values in the group of animals aged 4 to 9 years. Bretons are considered cold-blooded animals, which is consistent with the observed blood count values. However, it is concluded that these horses have biochemical values similar to warm-blooded breeds.