Mew has National Pokédex number 151 in Generation I Pokémon.
Mew is the final entry in the original National Pokédex, following Mewtwo at number 150. It is a Psychic-type Mythical Pokémon associated with rarity, hidden appearances, and the idea that its genetic material contains the information of other Pokémon.
Mew was not normally obtainable through standard progression in the original Pokémon Red, Green, and Blue games. It was added late in development and became widely known through a special promotional distribution connected with CoroCoro Comic. Its hidden status helped create rumors and sustained interest after launch.
Mew is sometimes confused with Mewtwo because their names and lore are connected. Mewtwo is a laboratory-created Pokémon derived from Mew, but Mew remains the final numbered species in Generation I.