An attempt is made to prepare a novel set of polymer blends based on poly(vinyl chloride) (PVC), poly(ethylene-co-vinyl acetate) (EVA) and poly(styrene-co-acrylonitrile) (SAN). The thermal, flame and mechanical behaviour of these blends was investigated. Ternary blends of PVC/EVA/SAN were found to have excellent thermal stability and mechanical properties as compared to pure PVC and binary blends. Measurement of smoke and volatile gas evolution also revealed that the ternary blends are very efficient in flame retardant applications.