The present study was conducted to examine the effects of drinking water carbonation on performance and pH value, pCO(2) and pO(2) of blood in male broilers exposed to heat stress. A total of 312, day old male broiler chicks were allocated to two groups with three replicates. During the 42 days experimental period while first group (control) received normal drinking water (pH 7.4) second group consumed carbonated drinking water (pH 5.7). No significant differences were observed between male broilers given normal and carbonated drinking water in terms of body weight, feed intake, feed conversion ratio and mortality. Birds treated carbonated drinking water has significantly lower blood pH and PO2 and higher blood pCO(2) compared to the control group. The results indicated that carbonated water might ameliorate blood acid-base imbalance caused by heat stress.