The present study was carried out to assess the efficacy of yeast probiotics and citric acid on growth performance of broiler . A 240 one day-old Cobb 500 broiler chicks were used. Each of the four groups, C-gr, CA-gr, PB-gr, and CO-gr contained 60 chicks and were randomly assigned to the experimental animals. The control group was given a standard diet and tap water. The CA group was given a standard diet and water that had been acidified (to a pH of 4.5) with citric acid monohydrate. Probiotics were given to PR group at a rate of 2x109 CFU per litre and Combination group received combination of PR 2x109 CFU / liter and CA in their drinking water 0.8 gm /liter. The treatments were continued for 5 weeks. Results revealed that LBW of combination group was significantly higher than other groups. Comparing CA gr to other groups, the gizzard weight was significantly (P0.05) higher in CA gr. Liver weight revealed significant increasing in all treated groups. Heart weight also showed a significant increasing in CA and PR groups. MDA level showed significant decrease in all treated groups. GSH level significantly (p<0.05) elevated in PR and combination groups. Serum T3 elevated significantly (p<0.05) in PR and combination groups while serumT4 elevated with significant (p<0.05) rate in all treated groups. CA, PB, and CO groups showed a significant (P0.05) decrease in TC and TG. In all experimental groups, HDL-C showed a significant (p0.05) elevation, while LDL-C resulted in highly significant reduction .