Abstract A histochemical study of some enzymatic steps in intermediary metabolism and glycogen synthesis in the regenerating limb of the adult Triturus viridescens is presented. There is increasing activity of the pentose phosphate shunt, an alternate pathway of carbohydrate metabolism, associated with dedifferentiation as demonstrated by a striking increase in glucose 6-phosphate dehydrogenase activity and relative reduction of the Krebs cycle enzymes. This pathway may be a source of ribosyl units for the increased synthesis of nucleic acids which has been demonstrated by other workers to occur with dedifferentiation. With differentiation there is a recrudesence of activity of the Krebs cycle enzymes. Of all the differentiating tissues cartilage shows the most intense activity of the Krebs cycle enzymes. No striking differences are noted in the oxidative enzyme pattern of the apical cap in comparison to normal epidermis. However, significant quantities of glycogen accumulate in the cytoplasm of the apical cap cells. Other qualitative, quantitative, and distributional changes noted in enzyme activity and glycogen content with dedifferentiation and redifferentiation are presented, and their significance is discussed. An effort is made, where possible, to integrate these facts with prior data obtained by other workers from a variety of experimental techniques including electronmicroscopy and radioautography.