For the investigations of the usefulness of immunoglobulin Y (IgY), we attempted to produce and isolate IgY from egg yolk of white Leghorn hens immunized with fetuin as a model antigen. We used three methods to optimize the recovery of IgY: water dilution, polyethylene glycol, and carrageenan. The daily yield of anti-fetuin IgY from egg yolk was also examined, and it was isolated using a fetuin-affinity column at a yield of IgY of 2.7% from total IgY Furthermore, peroxidase-labeled antifetuin IgY was prepared, and was used to determine the minimum sensitivity against fetuin, which was found to occur to a fetuin concentration of 1 ng/$mell$.