In order to determine if mutant hemoglobins can be identified by relatively simple methods, a Working Group of the ICSH Expert Panel on Abnormal Hemoglobins and Thalassemia analyzed 17 hemolysates containing 14 different mutant hemoglobins by four electrophoretic methods: (1) cellulose acetate in alkaline buffers, (2) citrate agar pH 6.0, (3) urea 2-mercaptoethanol buffer pH 8.9, and (4) urea 2-mercaptoethanol buffer pH 6.0. The examined mutants included several of great numerical and clinical importance as well as some rare ones, namely, HbS, C, D Los Angeles (Punjab), E, G Philadelphia, N Baltimore, and O Arab; also Hb Ft. Worth, Montgomery, Winnepeg, Rush, Q India, Bethesda, and Lepore. Comparative mobilities of these hemoglobins in all of the methods are presented here. The combined data permit their presumptive identification, often with a high degree of specificity. The system has been applied in Iran, where the four prevalent mutants can be differentiated by these methods, at considerable saving of time and resources previously expended on structural analyses. It is proposed as a basis for an ICSH Tentative Standard. There is little doubt that this presumptive identification of hemoglobin variants by simple electrophoresis will be improved or complemented by the introduction of newer techniques, such as immunologic analysis. However, for the present and for some time to come, the system outlined here should be found valuable. The present report does not concern itself with the numerous auxiliary techniques involved in the identification of abnormal hemoglobins-sickle-cell test, solubility tests, lability test-- and no claim is made that the simple system described here eliminates these other techniques from the diagnostic armamentarium of the laboratory.