Lysozyme was linked to a glycopeptide of ovomucoid and the modified enzyme was purified by affinity chromatography. The modified lysozyme showed a relative activity of 34 % compared to the native enzyme. The molecular ratio of the glycopeptide to the enzyme was 1.2. When the native and the modified lysozyme preparations were labeled with 125I and incubated with a rat liver membrane fraction in vitro, the modified enzyme showed a 4-fold higher affinity for the liver than the native lysozyme. Removal of sialic acid by neuraminidase enhanced further the binding, Experiments with the heart and the kidney gave less significant results, suggesting the specificity of the hepatic uptake of the modified lysozyme.