In bovine practice, different blood sampling sites are in use, e. g. jugular and udder vein. To evaluate the diagnostic accuracy of different blood parameters in relation to these two sampling sites, 12 clinically healthy, high-yielding German Holstein cows were double-sampled, first from the udder vein, then from the jugular vein, in order to minimize stress by restraint. Eighteen blood constituents were examined. Significant differences between udder and jugular vein blood were observed for values of 10 parameters (RBC, haemoglobin, PCV, AST, total bilirubin, glucose, urea, calcium, magnesium and inorganic phosphate). It can be assumed that stress caused by restraint is responsible for these differences. Therefore, sampling blood from the jugular vein does not lead to a higher diagnostic accuracy. In conclusion, considering especially aspects of labour economics, blood sampling from the udder vein seems to be a proper and highly reproducible method for bovine practice.