(1) The component I which is a lipoprotein isolated from immature egg of rainbow trout contained hexose, hexosamine, and sialic acid as the carbohydrate constituent, Mannose predominated over galactose and glucose. The carbohydrate content of the component 1 was lower than that of lipovitellin of hen's egg.
(2) The component I1 contained both hexose and pentose. It is suggested that the substance is a kind of glycoprotein similar to livetin of hen's egg yolk.
(3) The method for simultaneous determination of hexose and pentose was discussed.