AbstractUrea‐Triton polyacrylamide gel electrophoresis (UT‐PAGE) has been used to separate, in one dimension, membrane proteins present in red blood cells and hemoglobin chains associated with cell ghosts. The membrane proteins are especially well resolved in the high molecular weight range. The protein fractions were further characterized by two‐dimensional gel electrophoresis with UT‐PAGE in the first dimension followed by sodium dodecyl sulfate (SDS)‐PAGE and phosphorylation in the presence or absence of cAMP. A good recovery of spectrin and of band III was obtained in the two‐dimensional system. The proportion of α, β, Gγ and Aγ globin chains can be determined in comparison to the membrane proteins.