Recent developments of isoelectric focusing (IEF) are summarized. New approaches to the synthesis of carrier ampholytes are described and some controversial aspects of their properties, especially in regard to their molecular weight, are critically discussed. New aspects of preparative techniques, such as "steady-state rheoelectrolysis" and continuous-flow recycling IEF, are presented. New methodological trends of analytical IEF, such as agarose, cellulose acetate, ultrathin-layer and sub-zero temperature IEF are discussed. Among analytical applications, particular emphasis has been placed on detection of neutral mutations, IEF of peptides, IEF of cells and organelles and on titration curves. The review ends with a tiny chapter on a vast field, the explosive field of two-dimensional techniques.