The beta-glucan content in the groats of different Finnish oat varieties cultivated in Finland varied from 3.2 to 5.3% and, in the fibre concentrates obtained by dry milling and a further concentration step including hot ethanol treatment and wet milling, from 11.8 to 18.3%. The viscosities of the isolated crude extracts varied widely between the varieties. Stil, Puhti, Yty and Nasta formed the most viscous solutions and Pol, the typical feed oat, the least viscous solution. The more significant differences in the viscosities between the oat varieties when measured at the same beta-glucan concentration could be explained in terms of differences in mean molecular weight. Trypsin decreased the viscosity and the molecular weight of beta-glucan of all samples. The viscosity of the beta-glucan solutions was independent of pH both before or after enzyme treatment indicating that the protein or peptide is firmly bound to beta-glucan.