How can I catch Mew?

I am currently going through my old Pokémon Red and Blue games to complete my Pokédex, and I am almost complete, but I was wondering how I could catch Mew so I could have all 151 first gen Pokémon. I know you can do it with some complicated glitches that involve editing memory and such, but is there any simple way to do it that won't risk damaging my game?

Solution 1:

There seems to be a legitimate way of catching Mew that doesn't involve breaking the game and it's hex codes. Legitimate is a loose term here, as it's still a glitch that requires some good timing and patience.

Link is here, outline detailed below:

Preconditions

• Have a Pokemon that knows Fly.

If you have fought the following trainers, the glitch will not be able to be performed.

• Route 25 (Road to Bill's House) - Youngster w/ Slowpoke. He is the fourth trainer you come across after crossing Nugget Bridge, standing above a female trainer and looking North.

• Route 8 (Road between Lavender Town and Saffron City) - Gambler w/ two Poliwags and a Poliwhirl. He is standing just east of Saffron City, facing North towards the Underground Path.

Steps

1. On Route 8, stand in front of the door to the Underground Path. Save your game.

2. Walk down one step, and immediately press Start. If you succeed, the menu will pop up before the Gambler "sees" you. Go to the Pokemon that knows Fly, and fly to Cerulean. The Gambler will see you just before you fly away.

(A note - Your start button will no longer function until the completion of the next step)

3. Go North across Nugget Bridge, and find the Youngster trainer. The game will freeze up if you walk directly into him, so stay a few tiles away and wait for him to see you.

4. Battle him and defeat the Slowpoke. Your Start button will work again.

5. Fly to Lavender Town.

6. Head West onto Route 8. As soon as you enter the narrow path, a menu will pop up. Press B to exit, and a battle with Mew will begin.

I have not completed this glitch myself, and have only made a more clear and concise post from the linked source above. There's no guarantee that it will actually work.