Frosted Flakes ( North American countries ) or Frosties ( UK , Commonwealth of Nations and EU countries ) is a cereal like Corn Flakes from Kellogg 's , but coated with frosted sugar . Tony the Tiger has been the mascot in Frosted Flakes since it was first introduced in 1952 as Sugar Frosted Flakes ( the word `` sugar '' was dropped in the mid-1970s ) , and he is known for saying the cereal 's slogan : `` They 're grrreat ! '' . Tony the Tiger has been the mascot of Frosted Flakes since its introduction .