The present invention concerns reduced-yellowing thermoplastic or thermoset polymer compositions derived from the reaction of a diisocyanate, a polyol or polyamine, and a dicyandiamide. The present invention also concerns golf balls comprising the reduced-yellowing thermoplastic or thermoset polymer compositions derived from the reaction of a diisocyanate, a polyol or polyamine, and a dicyandiamide. The present invention also relates to a method for making a golf ball which includes using reduced yellowing compositions derived from the reaction of a diisocyanate, a polyol or polyamine, and a dicyandiamide. The resulting golf balls have similar processability and physical properties (such as resiliency and shear resistance) as golf balls made from conventional polyurethane or polyurea formulations, while exhibiting substantially improved resistance to yellowing.