Dimethyl and ethylene acetals of polyformylated unsaturated fatty esters were prepared, characterized, and evaluated as polyvinyl chloride plasticizers. Dimethyl acetals were prepared with trimethyl orthoformate as a water scavenger in the acid catalyzed acetalation reaction. With ethylene acetals, water was removed azeotropically. Although the acetals prepared were mixtures, molecular distillation gave diacetal esters of 80–90% purity and triacetal esters of 80–95% purity. The samples were characterized by gas liquid chromatography and by IR and NMR spectra. Compared to di-2-ethylhexyl phthalate as a plasticizer for polyvinyl chloride, the triacetal esters (both dimethyl and ethylene acetals) gave less migration and at least equivalent volatility characteristics; the triacetals also gave equivalent compatibility and strength, but somewhat less desirable low temperature and heat stability properties. The diacetal esters also had good compatibility, equivalent strength, somewhat better low temperature, but less desirable migration and volatility propert