The N,N-dimethylamides as well as a few N,N-diethylamides of a number of saturated and un-saturated long-chain fatty acids and fatty acid mixtures have been prepared, characterized, and screened as plasticizers for poly (vinyl chloride-vinyl acetate )copolymer. A number of ester-amides of short-chain 2-, 3-, and 4-hydroxyacids were included. All except the N,N-dimethylamides of stearic, palmitic, and epoxidized rapeseed fatty acids were compatible with the copolymer. Many of the N,N-dimethylamides were highly efficient plasticizers and, except for the dimer acid deriva-tive, were superior to di-2-ethylhexyl phthalate in this respect. A few of the dimethylamides were comparable with di-2-ethylhexyl adipate in low-temperature performance. The N,N,N′,N′-tetra-methylamide of dimer acid exhibited no measur-able volatility loss in copolymer compositions. 1So. Utiliz. Res. Dev. Div., ARS, D