There is little published information on the seasonal distribution of ewe mortality in hill flocks. This note presents records relating to some 1,500 Blackface and 1,000 Cheviot breeding ewes on three hill farms over a 10-year period from 1955 to 1965. The farms are Sourhope, Roxburghshire, in the Cheviot Hills, with 1,000 Cheviot and 350 Blackface ewes on predominantly Festuca-Agrostis, Nardus and Molinia pastures, subject to intermittent snow cover; Glensaugh in the East Grampians in Kincardineshire, with 550 Blackface ewes on predominantly heather (Calluna) pasture on free draining ground, subject to prolonged periods of snow which necessitate regular supplementary feeding; Lephinmore on Loch Fyne in Argyll, with over 600 Blackface ewes on mixed pastures mostly overlying peat, not liable to prolonged periods of snow. Further details are given in the H.F.R.O. report (1958).