In this study, the crystallization and melting properties of six different fat blends with the same saturated fat content (30%) but with a varying content of trisaturated and disaturated triacylglycerols were investigated using pulsed NMR, DSC and polarized light microscopy. Blends were either palmitic (P) or stearic (S) based, and were combinations of SatSatSat-rich (Sat = saturated) and SatOSat-rich (O = oleic) vegetable oils with high-oleic sunflower oil. The DSC results suggested that PPP forms mixed crystals with POP, leading to a better seeding of the crystallization process than did SSS with SOS. Some blends showed a two-step crystallization, which can be explained by polymorphism. Stop-and-return DSC results suggested an initial crystallization into an unstable polymorph followed by polymorphic transformation during the crystallization for those blends with significant amounts of SatSatSat. Polymorphic transformation was not seen for the blends with low SatSatSat. However, the microstructure of such blends changed dramatically during storage, while the microstructure of the blends with the higher SatSatSat content did not.