The assimilation of 57Co B12 from in vivo labeled eggs was much inferior to that of a comparable amount of crystalline 57Co B12. Furthermore, the absorption varied with the form in which the eggs were served. Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.