This study is a critical comparison of reported methods of purification of IgY from hen egg yolk. Five methods of lipid removal were compared, followed by a comparison of three methods of immunoglobulin precipitation. Each of these methods was tested three times. Lowry assays were used to measure the protein content of the various purified fractions, and densitometric analysis of SDS-polyacrylamide gels was used to quantify the proportion of IgY. Peak IgY yields of 15.6 and 15.1 mg of IgY per ml of egg yolk, with greater than 60% purity, were obtained after lipid removal using dextran sulphate and calcium chloride or phosphotungstic acid and magnesium chloride, respectively. Further precipitation of IgY from these fractions using 12% PEG, the most effective method of immunoglobulin precipitation, recovered pure IgY preparations, with mean yields of 8.80 and 8.62 mg per ml of egg yolk. Alternatively, a simpler and more cost effective method of lipid removal by freezing and thawing of egg yolk at neutral pH recovered 13.1 mg of IgY per ml of egg yolk at a purity of 71.1%. Subsequent Ig precipitation also recovered a pure IgY preparation with a mean yield of 7.49 mg per ml of egg yolk.