Egg albumen ovomucin distribution and composition were studied in fresh eggs with relatively low or high internal quality as indicated by Haugh unit (HU) values. Egg HU had been altered as a result of genetic selection (mean all eggs: 87 vs 73 HU) or by feeding vanadium (V) to hens (mean all eggs: 91 vs 80 HU). In both altered HU conditions, eggs with low HU values yielded signi®cantly less water-insoluble ovomucin from the thick albumen than eggs with high HU values, whereas the yield of ovomucin from thin albumen did not differ. The amount of ovomucin differed between eggs with high or low HU values as a result of feeding V, but the composition of ovomucin from the thick albumen was not affected. This was con®rmed by SDS-PAGE gels, carbohydrate contents, and amino acid contents. When HU values were different as a result of genetics, ovomucin was affected differently. The total amount of ovomucin isolated from the thick albumen of the eggs with high HU was much higher than the amount isolated from the low HU thick albumen. The composition of the ovomucin was also different. SDS-PAGE gels showed a greater proportion of the highly glycosylated b-subunit in the ovomucin from the low HU eggs. Carbohydrate analyses showed higher concentrations of sialic acids, hexoses and hexosamines in the ovomucin from the low HU eggs. The only difference between the ovomucins in the amino acid content was that isoleucine was slightly higher in the high HU ovomucin.