The Master Ball in "Pokémon Crystal" is obtained by talking to Professor Elm after earning all eight Johto Badges. It can also be earned by chance from the Lucky Channel radio program.
- Earn all eight Johto Badges
Eight trainers in the Johto region offer a badge to the player for defeating them in battle. Acquire the Zephyr Badge from Falkner, the Hive Badge from Bugsy, the Plain Badge from Whitney, the Fog Badge from Morty, the Storm Badge from Chuck, the Mineral Badge from Jasmine, the Glacier Badge from Pryce and the Rising Badge from Clair.
- Talk to Professor Elm
Travel to Professor Elm's lab in New Bark Town. Talk to the professor to receive a Master Ball. This is the only guaranteed Master Ball the player receives in any given playthrough of the game.
- Play the Lucky Channel contest to win a Master Ball
The Lucky Channel radio program broadcasts from the Goldenrod Radio Tower in Goldenrod City. Once per week, the channel broadcasts a random OT ID number, which changes every Friday. If any Pokémon in the player's party or Pokémon Storage System has an OT ID that exactly matches the winning OT ID, the player wins a Master Ball as a prize. Talk to the man on the first floor of the Goldenrod Radio Tower to receive the prize.