Double Kamehameha (ダブルかめはめ波) is a two-handed version of the Kamehameha used by Goku. First, Goku puts his hands out at his left and right sides. Then, he discharges a blazing aura as he fires two Kamehameha energy waves out of each hand at the opponents, inflicting a huge amount of damage.
Goku first uses this attack during his battle against Frieza in his final form on Namek. When Frieza attempts to sneak up behind Goku from a mountain, Goku senses Frieza and blasts him with the Double Kamehameha.
He uses it among the many Ki Blasts he fires to destroy moving spiked balls on the first floor of Wheelo's fortress in the movie Dragon Ball Z: The World's Strongest. Goku later uses this attack against two of Turles' henchmen, Cacao and Daiz, in the movie Dragon Ball Z: The Tree of Might. When Gohan has been forcibly transformed into a Great Ape by Turles, Goku rushes to help Gohan, only to be interrupted by Cacao and Daiz's combined attack. However, Goku blocks the attack with an energy shield and flies up into the air to attack Cacao and Daiz with the Double Kamehameha, blasting them away down into the ground.
Later, Goku also uses a Double Kamehameha during the first round of his fight against Baby Vegeta, but Baby quickly dodges the attack.