Important parameters like supercooling and cooling rates affecting the melt crystallization of a polyunsaturated fatty acid (PUFA) mixture obtained from sunflower oil were investigated and compared via high-resolution polarized-light microscopy. PUFA was thermally characterized in a differential scanning calorimeter and the significant liquid-solid-phase transition temperatures determined were then implemented in the development of specific temperature profiles. Analyzed between two glass slides, induction times were found to decrease with low crystallization temperatures and the number of nuclei per unit area increased with higher supercooling and cooling rates. A comparison between the linear crystal growth rates of pure standards of each of the main fatty acids present in the PUFA mixture and the PUFA mixture itself indicated that the latter is much slower than that of each of its pure components.