Abstract: A chimney tile adapter plate for securing a chimney cap, chimney flue, spark arrester, or other chimney extension member to existing chimney tile. The tile adapter plate of the present invention includes a deflector plate, with flue opening, which rests upon the top edge or lip of the chimney tile; a collar surrounding the opening and upwardly extending from the deflector plate for attachment of the chimney extension member; a flexible, elongated band secured to the undersurface of the deflector plate, preferably by slotted brackets; and a hose-type adjustable clamp engaging both ends of the band for tightening and clamping the band about the chimney tile. The band, in being flexible, is usable on chimney tile of varying shapes and, in combination with the adjustable clamp, is usable on chimney tiles of varying circumference.