You don't need to catch every Pokemon to complete your pokedex you need to just see them but you can catch all of them if you want to.
all of them in the regional pokedex
You have see to many different pokemons. Then you will fill it (you have to every Pokemon to get national pokedex).
Please see the related link for a complete Pokedex from the Sinnoh region.
150 hope i helped :) Actually there are 151 pokemon in the Sinnoh Pokedex but you only have to see 150 to get the National Pokedex.
You have to see them
You have to see every Pokemon in the sinnoh region.
you can't
You don't need to catch every Pokemon to complete your pokedex you need to just see them but you can catch all of them if you want to.
YOU NEED TO FIGHT ALL POKEMON AND YOU WILL COMPLETE THE POKEDEX. AND THAT WILL HELP YOU TO GET THE NATIONAL POKEDEX BY TALKIN TO PROFESSOR OAK.
all of them in the regional pokedex
You have to have caught all of the Pokemon (not just see them) to complete the Pokedex to show to Gamefreak, or have it during a trade
if you mean national pokedex then you must complete your normal pokedex and show it to the professor. if you already have a pokedex and think that there is an international one then you are sadly mistaken
you need 150 Pokemon to get the national pokedex
150 Pokemon
you have to see every Pokemon in the game.So you have to complete the pokedex.
You have see to many different pokemons. Then you will fill it (you have to every Pokemon to get national pokedex).