The present study was carried out on ten clinically healthy adult buffaloes of 4 to 6 years of age. The parameters of acid-base balance (pH, pCO 2 , pO 2 , HCO 3 , SBC, ABE, SBE, SAT and O 2 ct) were measured simultaneously in venous and arterial blood. The results from this study revealed that the mean, minimum and maximum values of pH, pO2, ABE, SAT and O 2 ct were lower in the venous blood than in the arterial blood while the values of pCO 2 and HCO 3 were higher in venous blood than in the arterial blood. Wider differences were observed in the values of the respiratory parameters of venous and arterial blood. The differences found in the parameters of acid-base balance between both the kinds of blood revealed the restricted informative signifi cance of the venous blood. This calls for the use of arterial blood when it is necessary to assess the acid-base balance.