Although Cohn's microfractionation method number 10 was specifically devised to meet the conditions of protein concentration and distribution in human plasma, it is shown in this contribution that it may be applied to studies of canine plasma. Essentially all of the lipids of plasma are recovered in Fractions IV + V + VI and I + III. Only negligible amounts appear in Fraction II. Electrophoretic studies proved that the lipoproteins of Fraction IV + V + VI have the mobility of alpha globulins and those in Fraction I + III have the mobility of beta globulins.