The fourth season of the American television sitcom The Big Bang Theory aired on CBS from September 23, 2010 to May 19, 2011.

[1] Melissa Rauch and Mayim Bialik auditioned and were promoted to the main cast during this season as Dr. Bernadette Rostenkowski and Dr. Amy Farrah Fowler respectively.

[2] When returning to the series, she was shown working as a bartender instead of waitressing at her usual workplace, The Cheesecake Factory, to hide her injury.

Alan Sepinwall of Uproxx praised the additions of Bernadette and Amy to the cast, writing that "With Amy Farrah Fowler and Bernadette promoted to semi-permanent status, the show is now able to spend large chunks of each episode focusing only on the women, and in the process has made Penny a much more well-rounded character rather than just a foil for the nerds".

Mayim fits in perfectly in The Big Bang Theory cast and played off of Kaley Cuoco just as well as Emmy Award-winning Parsons".