AbstractCertain ester‐acetal derivatives of azelaaldehydic acid have been evaluated as a new type of plasticizer of PVC. In gerneral, these compouonds have high compatibility and impart excellent low‐temperature, mechanical, heat‐ and light ‐stability properties to the plasticized PVC. The 2‐ethylihexyl ester bis (2‐methoxyethyl) acetal, in particular, appeared to have the best combination of properties for a useful plasticizer. The results indicate that a unique and useful type of plasticizer‐stabilizer can be obtained from derivatives of azelaa