The Card Key (Japanese: カードキーCard Key) is a Key Item that is used to open certain doors blocking a players path in buildings. It has been featured in the first four generations.
The Card Key is found in Silph Co.'s head office building while under siege by Team Rocket. It is used to open doors on various levels of the building that the player was unable to pass before. It is found on the ground in a small corridor on the fifth floor. Finding Key Items in this manner is rare: most are given to the player as part of the storyline. The Card Key is only in Pokémon Red, Blue, Yellow, FireRed and LeafGreen Versions. It does not exist in Pokémon Ruby and Sapphire, but can be found in the coding of Pokémon Emerald. However, it is not obtainable.