This review primarily deals with methods for separations of hemoglobins. An introduction considers electrophoretic methods as well as those involving isoelectric focusing and chromatography. The main advantages or disadvantages of each procedure are discussed after each technical description. The chromatographic methods are mainly limited to those used in clinical biochemistry. The second section treats the main diagnostic problems typically met with in the field of the hemoglobinopathies and deals successively with the diagnosis of hemoglobinopathies in the adult and the newborn. Numerous variants have been described in the adult, and among them Hb-S and Hb-C variants are the most frequent. Unstable or high oxygen affinity variants of hemoglobin are also considered. Finally, a new strategy for diagnosis is proposed. A special section is devoted to the diagnosis of thalassemia syndromes. The prenatal diagnosis of hemoglobinopathies is also discussed in some detail with a view to preventing the birth of homozygous children. This update ends with a chapter on the interest of the assay of hemoglobins A1c in the pathology of diabetes mellitus.