Determinations of free and total saccharifying activity were made on 144 samples of barley, and free saccharifying activity (Lintner value) was also determined on kilned malts made from these barleys. The samples represent 12 varieties of barley grown at 12 widely separated experimental stations in Canada.Varietal differences were demonstrated with respect to each determination. In total barley activity and malt activity, Olli was outstandingly high; the remaining six-rowed rough-awned varieties, Pontiac, Mensury Ott. 60, O.A.C. 21, and Peatland, and the smooth-awned variety Velvet, also yielded comparatively high values; the two-rowed variety Hannchen gave intermediate values; and the two-rowed varieties Victory and Charlottetown 80, and the remaining smooth-awned six-rowed varieties, Nobarb, Wisconsin 38, and particularly Regal, were low in activity. With respect to free barley activity the varieties fell in the same order with the exception of Olli, Peatland and Charlottetown 80 which gave very low values. These three varieties have only about 22% of total barley amylase in free form whereas figures for the other nine varieties range between 38 and 44%.There is a close correlation (r = 0.997) between total barley activity as measured by the papain and hydrogen sulphide methods, the former giving rather higher values. Varieties that are high in total barley activity also tend to be high in malt activity (papain, r = 0.904; H2S, r = 0.868). A similar relation exists between free barley activity and malt activity for nine of the varieties (r = 0.971), but if the three varieties having low percentages of free amylase are included the correlation is not significant (r = 0.217). Environment affects each property in essentially the same manner so that mean values for the different stations fall in much the same order for each determination and correlation coefficients for station means are all high.The possible utility of determinations of total barley saccharifying activity for facilitating the selection of strains of good malting quality from collections of hybrid lines is discussed.