The Aim of this study was study the influence of probiotic (MiaClost) supplementation on carcass yield, chemical composition and meat quality of broiler chick. The experiment applied on one week old chicks to the following treatments: Control: (control treatment: 0.00 MiaClost /liter of drinking water), T2: (adding 0.160 gm. MiaClost /liter of drinking water), T3: (adding 0.175 gm. MiaClost /liter of drinking water), T4: (adding 0.190 gm. MiaClost /liter of drinking water). After 42 day of experimental period, the parameters results were, results of live body weight, carcass weight traits showed in significant (p<0.01) differences among treatments, results of chemical composition, showed that supplement of probiotic lead to significant (p<0.01) decrease moisture percentages in breast and thigh meat, significant (p<0.01) increase protein percentages in breast and thigh meat, while in significant (p<0.01) effect in Fat and Ash of two type of meat. For physical traits, the probiotic supplementation not effect on pH of Breast and thigh meat, while lead to significant (p<0.01) increase in water holding capacity percentages in breast and thigh from 2nd treatment and decrease in 3rd treatment group, cooking loss affect significantly (p<0.01) by using probiotic, that breast and thigh meat in 3rd treatment has higher percentages, while the lowest percentages recorded in breast and thigh meat of 2nd treatment.