Episode Guide :: Season 4

# Episode Title Original Air Date User Rating
401 The Robotic Manipulation September 23, 2010  4.6 
402 The Cruciferous Vegetable Amplification September 30, 2010  4.5 
403 The Zazzy Substitution October 7, 2010  4.6 
404 The Hot Troll Deviation October 14, 2010  4.3 
405 The Desperation Emanation October 21, 2010  4.3 
406 The Irish Pub Formulation October 28, 2010  4.3 
407 The Apology Insufficiency November 4, 2010  4.4 
408 The 21-Second Excitation November 11, 2010  4.6 
409 The Boyfriend Complexity November 18, 2010  4.6 
410 The Alien Parasite Hypothesis December 9, 2010  4.2 
411 The Justice League Recombination December 16, 2010  4.7 
412 The Bus Pants Utilization January 6, 2011  4.2 
413 The Love Car Displacement January 20, 2011  4.4 
414 The Thespian Catalyst February 3, 2011  4.1 
415 The Benefactor Factor February 10, 2011  4.3 
416 The Cohabitation Formulation February 17, 2011  4.4 
417 The Toast Derivation February 24, 2011  4.6 
418 The Prestidigitation Approximation March 10, 2011  4.6 
419 The Zarnecki Incursion March 31, 2011  4.8 
420 The Herb Garden Germination April 7, 2011  4.7 
421 The Agreement Dissection April 28, 2011  4.5 
422 The Wildebeest Implementation May 5, 2011  4.3 
423 The Engagement Reaction May 12, 2011  4.4 
424 The Roommate Transmogrification May 19, 2011  4.6 

Season 4 DVD

Available now

Relive the complete fourth season of The Big Bang Theory again with this three-disc DVD box-set. Featuring all twenty-four episodes of the show's fourth season along with never-before-seen bonus features.

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Season Recap

The Big Bang Theory's fourth season focuses on character growth as Sheldon enters a platonic relationship with Amy, Howard restarts his romance with Bernadette, and Leonard starts a serious relationship with Raj's sister Priya.

As Sheldon becomes comfortable spending more time with Amy, his "girl who is a friend but not a girlfriend", starts to spend more time with the group and forms friendship with Penny. Howard's girlfriend Bernadette also becomes a part of the group. After dating for a few months, Howard and Bernadette get engaged after he proposes.

Leonard enters a long-term relationship with Priya, Raj's sister, after she moves to Pasadena. Seeing Leonard with another women, Penny begins to regret breaking up with him. In the season finale, after a night of drinking, Raj and Penny get very close.

The Big Bang Theory's fourth season contained twenty-four episodes aired between September 23, 2010 and May 19, 2011. For its fourth season, The Big Bang Theory moved to Thursdays at 8:00 on CBS, to form a new comedy block. Although the show continued to perform well in the ratings, it fell somewhat from the third season. The new timeslot lacked the strong lead-in the show had on Mondays, with TV's then-#1 sitcom Two and a Half Men, and suffered fewer people watching TV at the earlier time. Kaley Cuoco was absent from two episodes during the season, due to a broken leg from a horseback-riding accident.