In trial 1, eggs from young (28 wk) and old (65 wk) leghorn breeders were categorized into groups with mean weights of 54, 59 or 64 g. Female chicks were cage-reared to 18 wk of age; three rearing treatments involved five replicate cages of nine pullets from each egg size category, while treatment 4 involved a mixed population. The largest eggs contained most yolk fat and protein and albumen protein (P < 0.05). Egg size had no effect on male chick composition (P < 0.05). There was no overall effect of egg size or breeder age on feed intake of pullets, although up to 8 wk of age, pullets from small eggs were consistently smaller than those from large eggs. Egg size and breeder flock age had no effect on pullet weight at 18 wk. Pullets reared as a combination group of small:medium:large (3:3:3, treatment 4) showed a significant (P < 0.05) egg size effect on pullet weight at 18 wk of age. In a second trial, eggs were collected from a 45-wk-old flock of commercial leghorn breeders. Eggs were set according to weight, with mean egg weights of 56.4, 61.1 or 66.8 g. Rearing treatments related to the three egg size categories were represented by 10 replicate groups of nine birds each. A fourth treatment involved 26 groups of three chicks from each of the egg weight treatments. Breeder egg size had a significant effect on pullet weight at 126 d. With this differential maintained through the first 12 wk of lay. Breeder egg size had no effect on egg production (P > 0.05), although mean commercial egg weight and feed intake (P < 0.01) were directly proportional to hatching egg size (P < 0.01). It is concluded that hatching egg size can have a significant effect on life-cycle performance of leghorns, and as such, there may be scope for differential management of pullets hatched from different sizes of egg. Key words: Pullet, egg size, egg composition