Hardfats, or fully hydrogenated oils, consist of materials with homogeneous composition, composed of high melting point triacylglycerol. Hardfats are regarded as relatively new materials, and remain unexplored in lipid technology, notwithstanding being low-cost industrial products. They can behave as modulators of the crystallization process, acting as preferential nuclei for ordering the crystal lattice and inducing specific polymorphic habits, with great potential for use in crystallization processes. This work evaluated the influence of the addition of different hardfats on the crystallization patterns of cocoa butter (CB). Fully hydrogenated oils with significantly different chemical composition, obtained from palm kernel oil (FHPKO), palm oil (FHPO), cottonseed oil (FHCO), soybean oil (FHSO), and crambe oil (FHCrO), were considered. Blends of CB/hardfats, at concentrations of 1%, 3%, and 5% (by weight) were produced and the crystallization isotherms, thermal behavior, and polymorphism determined. Hardfats FHPO, FHCO, FHSO, and FHCrO proved to be effective additives to modulate the crystallization characteristics of CB, in respect to crystallization kinetics and thermal behavior. Only the hardfat from crambe oil, FHCrO, presented stabilizing effect on the polymorphism of CB, delaying the transition V ! VI.Practical applications: The use of hardfats as crystallization additives in products containing CB, for technological adjustment of CB formulations in order to harmonize events like solidification kinetics, thermal behavior, and polymorphism. Hardfats may act as potential modulators of CB crystallization, with the purpose to obtain higher quality products at significantly reduced cost in industrial processing.