The phenomenon of multiple melting endotherms is investigated for the blend system isotactic/atactic poly(beta-hydroxybutyrate) (PHB) for solvent-cast and melt-crystallized samples. It is shown that a melt/recrystallization process is operative for both methods of blend preparation. The overall melt behaviour is rationalized in terms of annealing of as-formed crystals and recrystallization of this material. Variations in d.s.c. scan profile with blend composition are ascribed to changes in the magnitude of the recrystallization exotherm. The crystallinity of the isotactic phase is shown to be invariant with composition. It is demonstrated that the solvent-cast blends are not fully miscible prior to the first melt.