The influence of time in the storage of blood samples at from 0°C to 5°C on the parameters of acid-basic balance, i.e. pH, pCO₂ and act ∙ HCO₃ — in the blood of 47 samples, collected at random from cows, was assessed. The determinations of pH and pCO₂ were done twice. First after 3 hour transportation in a cool box and later after 21 hour storage in a refrigerator at 5°C. No statistically significant differences were found. The findings indicate that under proper conditions the above parameters can be performed up to 24 hours since the collection of blood samples.