Regeneration is the ability to quickly grow back lost tissue and heal wounds and diseases at a faster than normal rate. Several kaiju have some sort of regenerative ability, and it is a fairly common power among them. When combined with enhanced durability, it can make some kaiju almost indestructible.
- Godzilla: Godzilla possesses a very potent regenerative ability, the speed of which may vary by movie. It is central to the plot of Godzilla vs. Biollante and Godzilla 2000: Millennium. In the latter, it was explained that Godzilla has a special substance in his cells that helps him regenerate tissue very quickly, called "Organizer G-1" (or "Regenerator G-1" in the U.S. version). Godzilla seemed to boast advanced regeneration due to his meltdown in Godzilla vs. Destoroyah, as he seemed relatively unaffected (despite losing massive amounts of blood) by Destoroyah's Horn Katana, even though the Precambrian kaiju sliced straight through his body multiple times.
- King Ghidorah: In Rebirth of Mothra III, King Ghidorah was able to regenerate his entire body from a severed tail.
- Frankenstein: In Frankenstein vs. Baragon, Frankenstein possesses a regeneration powerful enough to grow back his hand very quickly.
- Gaira and Sanda - In War of the Gargantuas, both of the Gargantuas display heavily enhanced regeneration derived from their predecessor, Frankenstein, both growing from only a few surviving cells.
- Hedorah: Hedorah has the capacity to regenerate by dividing. This is displayed after Hedorah is dried out by the Giant Electrode, but his husk of a body splits open and releases a fully-healed Hedorah. However, if all of Hedorah's body is dried out and no living material is left behind, he will be unable to regenerate.
- Biollante: Since Godzilla's cells were used in Biollante's creation, she also possesses his ability to regenerate, and is said by Dr. Shiragami to be immortal. However, Biollante's regeneration takes time, and she had to retreat at the end of Godzilla vs. Biollante to recover and regenerate the crippling damage to her body from Godzilla's atomic breath.
- Destoroyah: Destoroyah can regenerate in an unusual fashion - by breaking down into a horde of his aggregate forms, Destoroyah can then reform into his complete form to regenerate and remove any injuries he is suffering from. However, this takes time, and gives opponents a chance to weaken him in the process.
- Mothra Leo: Despite being grievously wounded in his battles with King Ghidorah, leaving him on death's door and his wings shredded, Mothra Leo was completely healed and transformed into Armor Mothra when a group of Primitive Mothras sealed him inside a cocoon.
- Orga: Orga gained Godzilla's regenerative ability by absorbing his cells, but was able to regenerate at an accelerated rate. Orga was able to regenerate his entire shoulder in a matter of seconds after Godzilla blasted it off with his atomic breath.
- Grand Flasher: Although unable to heal himself, Grand Flasher is capable of reviving deceased kaiju, and eventually did so to form an army of regenerated monsters.
- Greenman: Because Greenman is a machine, he can't regenerate damage he receives on his own, but when the Green Calls are used, the devices emit a signal which prompts his body to repair itself.
- Maoh: Similarly to Grand Flasher, Maoh is capable of reviving previously living monsters, notably Jairock.
- Gamera: In the Heisei series, Gamera has the ability to regenerate wounds he sustains in battle. This regeneration is not instant, and Gamera must rest for a period of time in order to heal. Because of Gamera's bond with Asagi Kusanagi, which causes her to also develop any wounds that Gamera sustains, her wounds heal along with Gamera's.
- Gyaos: In Gamera vs. Gyaos, Gyaos was able to regrow its foot, which it intentionally severed with its own sonic beam in order to escape from Gamera.