The original Generation I games introduced 151 Pokémon species.
These species first appeared in Pokémon Red, Green, and Blue, the Game Boy role-playing games released during the franchise’s first generation. Their National Pokédex numbering runs from Bulbasaur at number 001 to Mew at number 151.
The total includes familiar starter Pokémon such as Bulbasaur, Charmander, and Squirtle, as well as legendary Pokémon including Articuno, Zapdos, and Moltres. Mew was the final numbered species, although it was not normally obtained during ordinary play in the original games.
A common mix-up is counting only the Pokémon available in one cartridge. Red and Blue contained version-exclusive species, so players needed trading to complete the full original Pokédex. Later generations expanded the roster, but 151 remains the defining number associated with the franchise’s 1996 beginning.