A series of experiments are reported which show that reasonable assumptions for analysis of solute redistribution in solidification of castings and ingots include: negligible undertooling before nucleation of solid phases, negligible increase of solute in advance of the tips of growing dendrites, complete diffusion within the liquid over distances the order of dendrite arm spacings, platelike dendrite morphology. Qualitative and quantitative agreement of analysis with experiment is obtained for Al-Cu alloys from measurements of 1) amount of nonequilibrium second phase, 2) minimum solute content at the centers of dendrite arms (after solidification), and 3) change in minimum solute content in dendrite arms during solidification.