~ Mr. Slate's famous catchphrase (shouting Fred Flintstone's name).

Mr. Slate is Fred Flintstone and Barney Rubble's argumentative and hot-tempered boss at the quarry and a supporting character from The Flinstones. Although he is not a villain, he just bosses Fred and Barney around. Slate is extremely cheap, penurious, tightfisted, materialistic, and competitive, so he cares about money. Slate is also power-hungry and manipulative. He threatened to fire Fred and Barney a million times, but he always re-hires them. The only reason is, no one run the bronto crane like Fred and Barney. That's the only way Slate makes a lot of money is the bronto cranes.

Mr. Slate was born in Granite Town and lived at 140 Boulder Avenue. Right next door at 142 Boulder Avenue is his sister Flo Slate Rubble, mother of Barney Rubble.

He was voiced by the late John Stephenson (who would later voice Thundercracker in the original Transformers TV show).

Movie appearance

Mister Slate

Mr. Slate

Mr. Slate made an appearance as a supporting character in the 1994 comedy movie adaptation The Flintstones and he was portrayed by Dann Florek who is well known for his best role as Captain Donald Cragen from Law & Order: SVU.



  • An ongoing gag with Mr. Slate is that they always change his name. It has changed from Sylvester to Nate, Oscar and even George.