According to Forbes magazine, Howard also banked an incredible $95million last year.
The news of Simon's almighty earnings closely follows the revelation that he is to father a baby with his friend's wife Lauren, thought to be around ten weeks pregnant, and he has been named in the couple's divorce papers.
That means that Simon, 53, could be called to the witness stand to reveal information about his personal wealth, estimated to be in the region of £225million, and possibly details about his relationship with Lauren.
Next on the on the Forbes list was TV and radio producer Glenn Beck, followed by Oprah Winfrey, who earned $77 million (an estimated £50million) for the same period.
While she came in at number four in terms of earnings, the talk show queen recently topped Forbes magazine's most powerful celebrities list.
The magazine's writer Dorothy Pomerantz said: "She still wields an enormous amount of power... She is taking this cable network (OWN) and turning it around just through the sheer force of her will, her connections and her ability."
New York property tycoon Donald Trump also appeared on American TV's rich list, along with Ryan Seacrest – who produces Keeping up with the Kardashians – and talk show host Ellen DeGeneres.
Top ten: Forbes American TV's rich list
1. Simon Cowell and Howard Stern - $95million
3. Glenn Beck - $90million
4. Oprah Winfrey - $77million
5. Dr Phil McGraw - $72million
6. Rush Limbaugh - $66million
7. Donald Trump - $63million
8. Ryan Seacrest - $61million
9. Ellen DeGeneres - $56million
10. Judge Judy Sheindlin - $47million