What is Mewtwo’s National Pokédex number?

Mewtwo’s National Pokédex number is 150.

Mewtwo is listed immediately before Mew, which is National Pokédex number 151. This ordering is a common source of confusion because Mewtwo was central to the first Pokémon movie, while Mew was the hidden final species associated with the original Pokédex count.

In the Pokémon world, Mewtwo was created from genetic material connected to Mew. The games describe it as a Pokémon engineered through repeated gene splicing and experiments, giving it exceptional psychic power. Its origin became a major story element in Pokémon: The First Movie—Mewtwo Strikes Back.

Mewtwo first appeared in the Generation I games and could be encountered late in Pokémon Red, Green, Blue, and Yellow after the player became Champion. Its number has remained 150 across the National Pokédex, even as later games added hundreds of additional species and introduced alternate forms such as Mega Mewtwo X and Mega Mewtwo Y.