Generation V introduced 156 new Pokémon, the most of any Pokémon generation.
The generation began with Pokémon Black and White, released in Japan in 2010 and internationally in 2011. Its setting, the Unova region, was designed with a stronger international influence than earlier regions and was inspired partly by the New York metropolitan area.
The new roster runs from Victini to Genesect in National Pokédex order. Unlike earlier generations, the original Black and White games largely restricted players to newly introduced Pokémon before the post-game, helping the region feel like a fresh start.
The total is often confused with the number available in a single game. Version exclusives, evolutions, mythical Pokémon, and post-game encounters affect what an individual player can obtain, but 156 is the generation-wide count of new species introduced.