In the electrophotographic printing market, a demand for printers with lower energy consumption has driven the need to design toners that are fusible at lower temperatures. It has been reported previously that the energy required for fusing a toner based on amorphous polyester (A-PES) can be reduced by including a crystalline polyester (C-PES) in the toner composition. The improved fusing ability of a C-PES-containing toner is attributed to the large drop in viscoelasticity of C-PES that occurs at its melting temperature. The fusing advantages provided by C-PES, however, can be accompanied by negative effects on the toner's storage stability and durability during printing. Thermal analysis of C-PES-containing toners reveals that the glass transition temperature (T_g) of a toner is dramatically reduced relative to the T_g of a similar toner without C-PES. The reduction in T_g caused by C-PES is linked to the loss in polymer crystallinity that occurs when C-PES is melt-mixed with A-PES during the toner kneading process. A key, therefore, to improving the storage stability and durability of a C-PES-containing toner is to achieve higher degrees of crystallinity in the toner. In this article, a thermal annealing process was investigated as a method to improve the storage stability and the durability of toner. The annealing treatment involved conditioning of the toner for controlled periods of time at temperatures between the T_g and the melting temperature of the toner. It was found that the annealing process promoted the recrystallization of C-PES in the toner, resulting in an increase in the T_g of the toner. It was revealed that the annealing process promoted the formation of nanometer-scale crystalline domains in the toner and that the crystalline domain size was dependent on the temperature at which the toner was annealed. Rheological evaluation of the annealed toners revealed that the melting temperature of C-PES-containing toner can be controlled by changing the temperature at which the toner is annealed. It was shown that the morphology of the C-PES domains in a toner can be controlled by annealing under the proper conditions to yield a toner that has good storage stability and durability simultaneously with low-energy fusing.