While hacking your game with ActionReplay or GameShark is always an option, the methods in which you can obtain Masterballs varies depending on what game you are playing.
Red/Blue/Yellow: Gotten from Silph Co. president after defeating Giovanni
( If you want 128 masterballs search "Missingno. Glitch" )
Gold/Silver/Crystal: Gotten from Prof. Elm before you catch Ho-oh/Lugia (he will call you and tell you to go see him)
Ruby/Sapphire/Emerald:
-A masterball can be found on the ground inside Team Aqua/Magma's Base at Lilycove
-You can win a Masterball for getting an exact ID number match at the lottery in the Lilycove department store.
FireRed/LeafGreen:
-you get 1 master ball in Silph Co.
Diamond/Pearl/Platinum:
-Prof. Rowan will give to you before Facing Dialga/Palkia/Giratina
-You can win a Masterball for getting an exact match at the lottery in the Jubilife television building.
HeartGold/SoulSilver: Gotten from Prof. Elm before you catch Ho-oh/Lugia (he will call you and tell you to go see him)
-You can win a Masterball for getting an exact match at the lottery in the Goldenrod Radio Tower.
there is no more masterballs in Pokemon platinum but not if you use cheats
Silph co.
not unless you trade one no.
sorry you cant but if you have any friends with the game and they have alot just ask them to trade you Pokemon with the masterballs then you take the masterballs and release the Pokemon that was holding it.(sorry if this is confusing)
You can get only one per game.
what is the code for 999 masterballs for pokemon platinum?
Short answer: You don't.
no you cant they hatch in pokeballs
Action Replay (AR) you get 999 of them
Win the lottery at Jubilife city.
there is no more masterballs in Pokemon platinum but not if you use cheats
Trade masterballs from other games to firered.
Go to the department store and mach all of the numbers or cheat for them.
INFINITY MASTERBALLS just do my trick Trade pokemon for pokemon holding masterballs take them away and trade for your pokemon back
just make a Pokemon hold a master ball and trade it.....if you have the patience to do that over and over that is.
One masterball is in Pokemon emerald. To find out more go to my site called www.miquel.ning.com
You trade 50 peolple and talk to a spy in Pokemon center castelia city