Data of 224 Merino breeding ewes, kept on artificial pasture in a favourable environment in the South Western Districts, were analysed. Means of greasy wool mass at 16, 28 and 40 months of age were respectively 8,41, 9,14 and 8,79 kg. The mean shorn body mass at 16 months of age was 50,8 kg and the number of lambs born per ewe mated was 1,05 at both 24 and 36 months of age. The mean repeatability of greasy wool production was 0,76 ± 0,024.