This study was designed to determine the effect of feeding varying concentration of probiotics on growth performance in broiler chickens. A total of 81 day-old broiler chicks were used for this experiment, they were divided into three groups of 27 chicks each (n=27). Group A: No probiotics was administered and served as the control, Group B: birds were administered probiotics in feed at an inclusion rate of 0.5g/kg of feed, Group C: birds were administered probiotics in feed at an inclusion rate of 1g/kg of feed. Weekly weight gain and feed conversion ratio of each group of chickens was recorded for the six weeks experimental period. There was statistical significant difference (P≤0.05) in the weight gain and feed conversion ratio between the two experimental groups of birds (Groups B and C) fed probiotics and Group A (control) from the forth week to the end of the experiment. Groups B and C chickens had higher live weight and lower feed conversion ratio than group A chickens at the end of the experiment. However, there was no statistical significant difference (P≥0.05) in both the live weight and feed conversion ratio between groups B and C, fed different concentrations of probiotics. In conclusion, the use of probiotics supplemented in feed resulted in a significant increase in live weight and a lower feed conversion ratio in broiler chickens. It was therefore recommended that broiler chickens should be administered probiotics to help in weight gain and invariably maximize profit.