The appropriateness of the current adjustment factors for weaning weight was studied on data from the Swedish Sheep Recording Scheme for the years 1981–83 and 1986–88. The study included the four main breed groups Swedish Peltsheep (P), Swedish Landrace (L), Swedish Crossbred (X) and the imported heavy breeds (K). The adequacy of the adjustment factors was also tested within the breeds Swedish Finewool (Lf), Swedish Rya (Lr) and Crossbred group having crossbred parents (X*X). Analyses (1981–83) were based on 140681 Pelt lambs, 16785 lambs from the L-group, 25092 lambs from the X-group and 6321 lambs from the K-group. Data from 1986–88 comprised in total 11% fewer lambs.