Abstract Dressing percentage of 922 second-cross lambs rose as liveweight and fatness increased. Lambs weighing 35 kg and sired by Poll Dorset (PD) and Suffolk rams had dressing percentages of 44.7 and 43.4%, respectively. For PD sired lambs weighing 35 kg and fatscore 2 and 4, the dressing percentage increased from 44 to 49.7%, respectively. There was no significant difference between ewe and wether PD sired lambs for carcass weight/liveweight relationships with both groups having similar levels of fatness. Carpetwool lambs (114) had lower dressing percentages than second cross lambs. In contrast to second cross lambs the dressing percentage of carpetwool lambs decreased with increases in liveweight.