The body weights of pig and litter at weaning at 30 days of age were compared between three-breed cross and backcross swine by least squares method on the basis of the data from 2,310 litters of three-breed crosses and 227 litters of backcrosses produced from crossbred Yorkshire-Landrace, Duroc-Yorkshire and Duroc-Landrace dams mated to purebred Duroc, Landrace and Yorkshire boars. The results obtained in this study are as follows. 1. The three-breed crosses, D x YL, L x DY and Y x DL tended to have heavier individual pig weight and litter weight at weaning than the backcrosses. The average superiority of the three-breed crosses over the backcrosses expresses as percentage of the backcross mean was 1.8% for the individual pig weight and 3.0% for the litter weight at weaning. 2. None of the contrasts between sire breeds or between crossbred dam groups was statistically significant for the two traits studied. 3. The results obtained in this study indicate that the use of three-breed cross is preferable to the backcross in order to have heavier pigs and litters at weaning.