Season 1 (2005–06)Edit

Image Title Number Original Airdate
150px And Then There Were 10 1 December 27, 2005
Ben gains a device, the Omnitrix, which allows him to transform into many aliens with incredible powers!
150px Washington B.C. 2 January 13, 2006
A sinister and cruel scientist by the name of Aloysius Animo wreaks havoc on Washington.
150px The Krakken 3 January 14, 2006
A man named Jonah steals the Krakken's eggs, causing the lake monster to go wild.
150px Permanent Retirement 4 January 21, 2006
Ben visits his great Aunt Vera in a retirement home, but discovers that creatures called the Limax are taking over residents' bodies.
150px Hunted 5 January 28, 2006
Vilgax sends three bounty hunters to get the Omnitrix, but they have a tough time doing so.
150px Tourist Trap 6 February 4, 2006
Ben visits Sparksville, a town full of cheesy exhibits, and unintentionally lets loose an alien with a dangerous sense of humor.
150px Kevin 11 7 February 11, 2006
After a fight with Grandpa Max, Ben makes friends with a kid called Kevin, who goes mad with power!
150px The Alliance 8 February 18, 2006
When Grandpa Max gets injured in a fight, Ben decides that he and Gwen are better off without him.
150px Last Laugh 9 February 25, 2006
When an evil circus clown kidnaps Gwen, Ben must conquer his fear of clowns to stop him.
150px Lucky Girl 10 March 4, 2006
When Ben gives Gwen a luck charm, she decides to become a hero called "Lucky Girl".
150px A Small Problem 11 March 11, 2006
Ben (as Grey Matter) gets caught by a man named Howell, who hands him over to the Forever Knights.
150px Side Effects 12 March 18, 2006
Ben catches a cold, which turns out to have interesting side effects on his aliens when he battles a bug villain named Clancy.
150px Secrets 13 March 25, 2006
Ben encounters his most deadly enemy yet: Vilgax, who plans to steal the Omnitrix and use it to rule the universe!

Season 2 (2006)Edit

Image Title Number Original Airdate
150px Truth 14 May 29, 2006
The gang meet an old colleague of Grandpa who is not all he seems.
150px The Big Tick 15 May 30, 2006
Ben has to face a new, extremely dangerous threat, using a brand new alien.
150px Framed 16 May 31, 2006
Kevin is back! This time he frames Ben of being a menace, before merging into an incredibly powerful form!
150px Gwen 10 17 June 1, 2006
Ben wakes up in an alternate world where Gwen finds the Omnitrix.
150px Grudge Match 18 June 7, 2006
Ben and Kevin are taken on board an intergalactic wrestling ship. Now they must put aside their differences to escape...if they survive first.
150px The Galactic Enforcers 19 June 13, 2006
A group of super heroes team up with Ben to defeat Sixsix and Vulkanus who plan on building a bomb that could destroy the solar system.
150px Camp Fear 20 June 21, 2006
Ben goes to a camp which has been taken over by alien plants.
150px Ultimate Weapon 21 July 6, 2006
Grandpa Max starts behaving differently when the Forever Knights plan to steal the Sword of Ek Chuaj.
150px Tough Luck 22 July 12, 2006
Gwen needs to become Lucky Girl again when Hex and Charmcaster return for vengeance.
150px They Lurk Below 23 July 18, 2006
Ben encounters the cause for the Bermuda Triangle.
150px Ghostfreaked Out 24 July 25, 2006
Ghostfreak escapes from the Omnitrix and vows Ben's body!
150px Dr. Animo and the Mutant Ray 25 August 25, 2006
Dr Animo returns whilst Ben has some problems with his alien forms.
150px Back with a Vengeance 26 October 9, 2006
Ben unlocks an unstoppable combination on the Omnitrix! And since Vilgax and Kevin join forces, he's going to need it!

Season 3 (2006–07)Edit

Image Title Number Original Airdate
150px Ben 10,000 27 November 25, 2006
Ben travels to the future and meets his older self but finds out he is not all he expected.
150px Midnight Madness 28 December 2, 2006
An evil hypnotist prepares to turn all the people in a shopping mall into his own slaves...forever!
150px A Change of Face 29 December 9, 2006
Charmcaster returns with a new, mastermind plan to get the Omnitrix.
150px Merry Christmas 30 December 11, 2006
Grandpa Max is kidnapped and turned into a fake Santa Claus.
150px Benwolf 31 February 17, 2007
Ben is attacked by the Yenaldooshi and is beginning to turn into a werewolf - or is he?
150px Game Over 32 February 24, 2007
Ben and Gwen are sucked into Ben's favorite game, Sumo Slammers!
150px Super Alien Hero Buddy Adventures 33 February 24, 2007
Ben finds people making shows about his alien forms.
150px Under Wraps 34 March 10, 2007
Ben faces a tough fight with a Mummy who possesses a strange crystal that could turn everyone into a monster!
150px The Unnaturals 35 March 17, 2007
Ben finds out that Cash and J.T. are playing a baseball match. However the opposing team is not real. They're too perfect...
150px Monster Weather 36 March 24, 2007
A weather machine goes out of control and starts making weather monsters!
150px The Return 37 April 7, 2007
Dr Viktor, the Yenaldooshi and the Mummy team up to bring Zs'Skayr back.
150px Be Afraid of the Dark 38 April 14, 2007
Zs'Skayr plans to block out the sun and make the Earth a dark, dark place....
150px The Visitor 39 April 21, 2007
Grandpa Max's alien friend Xylene returns to Earth to give him the Omnitrix and Ben unlocks a brand new alien.

Season 4 (2007–08)Edit

Image Title Number Original Airdate
150px Perfect Day 40 July 14, 2007
Ben has a great day! But when the Forever Knights are shown to be behind it, it turns out to be a nightmare.
150px Divided We Stand 41 July 19, 2007
Ben unlocks a new alien, Ditto! Meanwhile, Dr. Animo returns with plans to utilize the Omnitrix for himself.
150px Don't Drink the Water 42 July 26, 2007
Hex returns for the water of the Fountain of Youth.
150px Big Fat Alien Wedding 43 August 2, 2007
The trio attend a wedding between a Tennyson and an alien.
150px Ben 4 Good Buddy 44 September 22, 2007
Three crooks steal the Rustbucket.
150px Ready to Rumble 45 September 29, 2007
Thinking he broke Gwen's laptop, Ben signs up for a wrestling tournament to get the money required to replace it.
150px Ken 10 46 October 6, 2007
In the future, Ken, the son of Ben, gets an Omnitrix... and a new best friend. But that friend has a connection with Kevin...
150px Ben 10 vs. the Negative 10: Part 1 47 March 9, 2008
Driscoll, the Forever King, creates a team to destroy Ben.
150px Ben 10 vs. the Negative 10: Part 2 48 March 9, 2008
Ben prepares for his greatest battle yet!
150px Goodbye and Good Riddance 49 April 15, 2008
Ben's done with summer, but Vilgax isn't done with Ben!