In 6 generations of ducks from 4 conservative groups: Khaki Campbell (Khl), Orpington (01), their crosses (KhOl) and Miniducks (K2), mean values of some meatness traits, their coefficients of variation (v, v_years) and repeatability (r_p) were estimated. Live weight of the 7-week-old birds and contents of the investigated tissue components in the carcass differed depending on the origin and sex of the birds. In all groups, lower v and v_years values of live weights in the 3rd and 7th week of life were found in females, while the r_p values were higher than those in males. High values of v (up to 22%) and of v_years (up to 26%) were found in 3-week-old drakes in live weight of 3-week-old drakes and in breast muscless content in the carcasses of 7-week-old males (up to 17 and 21%, respectively). High r_p values were found concerning the live weight of 7-week-old ducks (0.4-0.8), middlde r_p values concerning the live weight in 7-week-old drakes as well as those of per cent contents of breast and leg muscles in the carcasses of drakes and ducks (0.1-0.6), while they were low in 3-week- old birds and in the carcass contents of skin with subcutaneous fat in birds of both sexes (0.1-0.3). The highest live weight at the age of 7 weeks was noted in Orpingtons, but the highest content of breast muscles was found in Miniduck carcasses.