The breeding values of the Landrace boars were estimated bused on the records of the purehred Landrace and the crossbred between Landrace and Large Yorkshire by best linear unbiased prediction(BLUP) and least squares methods for litter size and 21-day weight to study the relationship between the breeding values estimated by the performances of purebreds and crossbreds. The data used in this study were the records of 3.170 litter of the Landrace purebreds and the crossbreds between Landraces and Large Yorkshires farrowed at the J. Swim Breeding Fann in Jeonnam Province from January. 1984 to December. 1991. The correlation between the breeding value, of the boars estimated on the basis of the purebred and crossbred performances by the BLUP was 0.253 for the litter size and 0.801 for 21-day weight. The correlation between the breeding values of the boars estimated on the basis, of the purebred and crossbred performances by the lest squares method was 0.712 fir the litter size arid 0.853 for 21-day weight.