Abstract. Haematological and biochemical parameters were examined in the blood of 87 cows, bulls and oxen of the indigenous Croatian breed, Istrian cattle. The sample represents 11.93 % of the total adult population. This breed is classified as highly endangered. The age of tested animals was between 2 and 17 years. Cattle were divided into three groups, animals aged 2 to 6 years (n=19), 7 to 10 years (n=37), and older than 10 years (n=31). Animals were kept in the area of Istria County, mostly in stables though occasionally at pasture. The cows were milked twice daily and gave an average of 1 000 litres of milk per year. Erythrocytes, leukocytes, haemoglobin, haematocrit and mean corpuscular volume were determined. Differential analysis was performed by counting blood cells in the blood smear after Pappenheim staining. Biochemical parameters such as total cholesterol, triglycerides, urea, creatinine, total bilirubin, calcium and inorganic phosphorus were determined. The activity of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase was determined by spectrophotometry. These biochemical and haematological parameters of this Istrian breed were within the physiological range, while slight deviations were observed for certain parameters. The greatest deviation from the physiological range was shown in the concentrations of urea and creatinine. These results may contribute to a better understanding of the metabolic profile and haematological indicators for estimating the physiological status of these endangered cattle in Istria, for further investigation and for diagnostic purposes.