The study was carried out to select the superior laying hens by crossing of 5 white Leghorn strains. The Colonial strain females which were imported from U.S.A. in 1967 were crossed with 4 different inbred strain male of White Leghorn. Body weights at 8 weeks, at first egg, at 300 and at 500 clays were heavier in crossbreds than in imported strain. Age at first egg was similar in crossbred and in imported strain. The egg weight of crossbreds(58.73g) was heavier than mid-parents but lighter than imported strain(60.57g). Crosshred, except for M×C, produced 24-27 more eggs than imported strain on the hen-housed basis. Feed requirement per 1㎏ egg production was similar between crossbed and imported strain. On the basis of the results of this study, to make maximum heterosis for egg production, it is recommended that Colonial inbred strain female should be cross with male of Sung Hwan, Darvy and Dembro strains.