|Buy:||Can't be bought|
|Sell:||Can't be sold|
|First Appearance:||Pokémon Red and Blue|
The Master Ball (Japanese: マスターボール Master Ball) is the best and rarest ball available in any game. It has a two-shade purple top forming two brighter purple circles on the sides of the top, as well as the letter "M" printed on the top. The Master Ball has a 100% chance to catch any Pokémon, no matter what the circumstances and could be described best as "the ball that never fails".
It was originally manufactured by Silph Co. in Saffron City, but only a few were produced before Team Rocket tried to steal them. Since then, they have been discontinued. From then on, the few remaining prototypes were only given to accomplished Pokémon researchers.
Only one can be found during the course of the story in each game. However, starting from Generation II, additional Master Balls can be won, albeit very rarely, from the in-game Lottery. More can also be gained by trading a Pokémon holding a Master Ball from another game.
- Red/Blue/Green/Yellow: Given by the President of Silph Co. after defeating Giovanni in Saffron City.
- Gold/Silver: Given by Professor Elm after getting the Dragon Fang from the Dragon's Den.
- Crystal: Given by Professor Elm after answering the Elder's test at the Dragon's Den.
- Ruby/Sapphire/Emerald: Found in a room of the Magma Hideout (Ruby)/Aqua Hideout (Sapphire and Emerald) between 2 Electrode and a Nugget.
- FireRed/LeafGreen: Given by the President of Silph Co. after defeating Giovanni in Saffron City.
- Diamond/Pearl/Platinum: Given by Cyrus after defeating him at Team Galactic's HQ.
- HeartGold/SoulSilver:Given by Professor Elm after answering the Elder's test at the Dragon's Den.
- Black/White: Given by Professor Juniper after defeating Iris/Drayden in Opelucid City; Trade 50 Pokémon through the GTS.
- Black 2/White 2: Given by Professor Juniper in Mistralton City;Defeat Colress at the Plasma Frigate once after beating the game (The frigate is docked in P2 Lab).
- It can catch any Pokémon without fail.
- It is considered the most powerful Poké Ball.
- The Generation V games are so far the only ones where it is possible to get more than 1 Master Ball without winning it from an in-game Lottery corner.
- Although it is widely believed there is a 100% chance of catching the Pokemon, this is not actually true. There is a 1 in 65536 chance that it will not work. However, this is more than 99.999%, and in the course of a game, it is utterly improbable that the Master Ball will fail. However, you cannot catch unidentified ghosts in the Pokemon Tower in Lavender Town, Black Kyurem (Black 2) and White Kyurem (White 2).
- Though production of it is believed to have been discontinued by Silph Co. following Giovanni's and Team Rocket's attempted takeover, given its appearence in other games it is more likely that the company still produces a limited number of Master Balls for use mainly by Pokemon researchers (such as Professor Oak and Professor Elm), high ranking members of the Pokemon League (such as the Elite Four and League Champion), those given away as Lottery Prizes, and possibly some for use by Silph Co. employees. It is also possible and likely that due to their capture rate their production and distribution is monitored and regulated by Pokemon League. Given Cyrus having a Master Ball in his possesion, it is likely that a few many have made their way into the hands of criminals via either theft or purchased on the black market.
- The Master Ball's rarity in both the games and anime is likely due to several factors:
- Team Rocket's attempted takeover of Silph Co. and attempt to steal the Master Ball (in the games only).
- In the both the games and anime, it's high capture rate would make catching wild Pokemon too easy and if it where easily available it could cause the number of certain pokemon in the wild to decrease due to over catching.
- Possible misuse or reverse engineering of it by Pokemon Poachers and criminal organizations such as Team Rocket, Team Aqua, Team Magma, the Cipher Syndicate, Team Snagem, and Team Galactic (in both the anime and the games).
- If Master Balls where commonplace it would likely render all other models obselete which could force Poké Ball manufacturers to discontinue some and/or all other types of Poké Balls, and its high capture rate would reduce the number of Poké Balls purchased by Trainers, due to a lack of failed captures (in the games, if a capture attempt fails the Poké Ball used is lost, a fact which encourages Trainers to purchase more Poké Balls to prevent running out and/or purchase Poké Balls to replace the ones that where lost due to failed captures).