Abstract: On a chromatogram wherein peaks corresponding to a plurality of classes of lipoproteins appear in a mixed form, components contained in the lipoproteins are quantitatively determined by class. The present invention comprises a first step of separating a plurality of classes of lipoproteins contained in a sample through liquid chromatography and assaying the components contained in the separated lipoproteins and a second step of dividing the chromatogram obtained in the above described first step by lipoprotein class and determining quantitatively the components contained in the lipoproteins by class.