The chromatography of four samples of insulin by elution analysis at con� stant pH and ionic strength on a diethylaminoethyl (DEAE).cellulose column has been studied. The presence of three components was apparent at pH 7�4 in a buffer containing 8M urea. The results are compared with those obtained on the same samples of insulin by other workers using countercurrent and chromatographic techniques. The experimental and theoretical curves for the major peak of the International standard insulin sample coincide.