Various extraction methods of vitamin B₁₂ compounds from eggs were investigated to clarify the forms of B₁₂ in eggs. The results were as follows : 1) A conventional extraction method of B₁₂ using 80% ethanol was not available for eggs. 2) As the effective B₁₂ extraction method, the following procedure was established, namely, heating egg homogenate for 30 min at 90°C with 1 % N-ethylmaleimide (1 M) in ethanol-0.1 M acetate buffer (pH 4.8) or 80 % ethanol-0.1 M acetate buffer (pH 4.8). 3) The content of vitamin B₁₂ analogues extracted with 80 % ethanol-0.1 M acetate buffer (pH 4.8) in fertilized egg was higher than in unfertilized egg. 4) The treatment of the precipitates obtained by the solvent extraction with pepsin led to more efficient extraction of vitamin B₁₂.