you can use action replay code manager or you defeat Cyrus in team galactic warehouse and he will give you a masterball
From the Lottories.
Help silph co then talk to the president he gives the masterball to you.
Save Silph Co., Just like in Blue.
You run into entei randomly and use a masterball
You can only get another masterball if a friend trades you a Pokemon holding the masterball they obtained.
mew-two is lvl. 70 in cerulian cave. make sure you save a masterball for him
go into UN inhabited plain and go to the end and zapodos will be there
Yeah go to route 1 until you find it then use the masterball.
It isn't meant for any one pokemon. Most people use it on Mewtwo, which you probably should use it on. You can catch the legendary birds and Mewtwo without a Masterball but it can take a long time.
You CAN'T make a masterball but you can win one at the Goldenrod Radio towerGo to Front desk. Main stuff is chance, hope, lots of pokemon (increases your chances) and then...YOU HAVE WON NUMBER ONE PRIZE MASTERBALL IF YOU ARE VERY LUCKY!!!!!
The only way to get more masterballs without cheating is to have other leafgreen versions or firered or ruby or sapphire or emerald or Pokemon colosseum or Pokemon xd gale of darkness trade the masterball that those games get to leafgreen other than that you have to win the lottery in ruby and sapphire and emerald at lilycove city to get another masterball then trade it to leafgreen.
This wont work, but you could try having to Pokemon hold Masterballs and mate them. Hope it works!