Protein extraction using reversed micelles is carried out in a packed column. The extracted fraction of lysozyme and the overall capacity coefficient, K(c)a, are measured for various flow rates and different packing materials. The same column without packings is also used as a spray column, By using a flat interface stirred cell, mass transfer coefficients for the aqueous and the organic phases are measured as well as the protein transfer rate, The results indicate that the resistance of protein solubilization at the interface controls protein transfer from the aqueous into the organic phase. The extracted fraction in the packed column is about three times larger than that for the spray column due to the larger holdup of dispersed phase in the packed column. Since the drops hardly break or coalesce in the packed bed and the protein transfer coefficient is constant, the overall capacity coefficient is controlled by the holdup of dispersed phase. On the assumption that the drop size and the transfer coefficient are constant, the correlation between holdup and now rates is obtained. Values of K(c)a and the extracted fraction are calculated from the holdup correlation. Effects of packing materials on the values of K(c)a are small. A high protein activity is retained in the packed column operation, which indicates that the packed column does little harm to proteins due to moderate mixing.