A BLEND OF A POLYPHENYLENE ETHER AND A STYRENE RESIN CHARACTERIZED BY THE ADDITION OF A SMALL BUT EFFECTIVE QUANTITY OF ELEMENTAL PHOSPHORUS. THE POLYPHENYLENE ETHERS ARE FLAME RETARDANT. THE ADMIXTURE OF A POLYPHENYLENE ETHER WITH A STYRENE RESIN DESTROYS FLAME RETARDANT PROPERTIES. IN ACCORDANCE WITH THE PRESENT INVENTION, IT HAS BEEN FOUND THAT THE ADDITION OF ELEMENTAL PHOSPHORUS, PREFERABLY ELEMENTAL RED PHSOPHORUS IN SMALL AMOUNTS, TYPICALLY FROM 0.1 TO 5% OF THE TOTAL COMPOSITINS, PROVIDES A BLEND HAVING EXCELLENT FLAME RETARDANT PROPERTIES. MOREOVER, OTHER PROPERTIES OF THE BLEND ARE NOT MATERIALLY AFFECTED BY THE ADDITION OF THE PHOSPHORUS.