The selected animals for the present study were 80 buffalo-calves of both sexes, 4-8 months old. These calves were subjected to careful clinical examinations. 60 calves showed the clinical sings of pneumonia, w hile the rest, 20 calves were clinically healthy. The present investigation aimed to study the extent of changes in blood gases, acid-base balwwe and serum electroly te values in association with pneumonia in buf falo-calves. Blood gas tensions, acid-base measurements and serum electroly te concen trations were determined in 10 pneumonic calves (diseased group) compared w ith cor- responding values of 10 healthy calves (control group). Blood gas analysis revealed signiftcant decrease (P<0.01) in both blood pH and oxygen tension (Po while carbondioxide tension ((Pco showed significant decrease (P<0.01). Bicarbonate (Hco3-J levels; total carbon dioxide (Teo and base excess (BE) in pneumonic calves, were insig niftcantly affected and still w ithin the normal physiological levels. Significant increase (P<0.05) in potassium levels with significant decrease (P<0.05) in chloride levels were detected in diseased buffalo-calves. The obtained data revealed that pneumonia in calves was associated with disorders in blood gases, acid-base balance and electrolyte values and that analysis of blood gases and acid-base status is very useful in evaluat ing the diagnosis and prognosis of pneumonia in calves.