Abstract: This study was conducted to determine the effect of egg weight on hatchability and chick hatch-weight of COBB 500 broiler chickens. A total of 396 COBB 500 hatchable eggs classified according to three different egg weight groups as small: (<49 g) medium: (50-59 g) and large: (60-69 g) were used in the experiment. A complete randomized design of three treatments, three replicates with each replicate having 44 eggs was used for the experiment. Simultaneously a linear type equation was used to determine the relationship between egg size and responses in hatchability values and chick hatch-weight. Results indicated that large-sized eggs produced chicks with higher (p<0.05) hatch-weight than medium and small-sized eggs. However, no differences were detected with fertility rate percentage, hatchability percentage and percentage hatch of fertile. It is therefore concluded from the result of the present study that sorting of COBB 500 broiler chicken breeder eggs by weight prior to incubation might be advantageous in producing uniform size COBB 500 broiler chicken hatchlings to meet specific market demands with improved efficiency.