The experimental designed to measure the effect of darkening programs on growth rates and some blood parameters in broiler chicks. Six hundred Ross308 chicks Wing-banded at 1-day old were divided into four trail groups, each with 3 replications. The chicks were raised on ground litter containing sawdust. Chick's were subjected to four darkness program: Treatment 1, serviced as a control (24 light + zero dark), Treatment 2 (18 L + 6 D continues when chicks arrived 150 g), Treatment 3 (1 hour of darkness at 2ndday, 2 hours of darkness at the start of the 2nd week, 3 hours of darkness at the start of the 3th week, 4 hours of darkness at the start of the 4 th week and 5 hours of darkness at the start of the 5th week) and Treatment 4 (1 hour of darkness from the 4th day until the 7th day, 4 hours of darkness from the 8th day until the 14th day, and 6 hours of darkness from the15th day until the 30th day). The results indicated that, the positive effect of the darkness schedule program which used in the experimental trail is treatment four.