$ ls bios/

Which one do I need?

PCSX2 will not boot without a BIOS. Match the BIOS region to the region of the game you are playing — a PAL game wants a European BIOS, an NTSC-U game an American one, a Japanese game a Japanese one. Every game page on this site shows its region in the spec table, so check there if you are not sure.

Beyond that the version rarely matters. Unless you have a reason to want an older revision, the cards above are the newest build for each region.

Putting it in PCSX2

1. Download the file for your region — it arrives as a .bin, already unpacked.
2. Drop it in the PCSX2 bios folder. On Windows that is usually Documents\PCSX2\bios; the emulator's Settings → BIOS screen has a button that opens the right folder for you.
3. Back in Settings → BIOS, hit refresh and pick the entry from the list.

Notes on the versions

• Versions 1.00 and 1.01 are Japanese only — the console launched in Japan in March 2000, and North American and European builds only start at 1.10.
• 2.10 is Japan-only; 2.30 is the last revision Sony shipped, in the late slim models.
• Asia (h) and China (c) builds are NTSC-J based. The Russian (r) build is PAL.
• Some dates appear twice for one region because Sony shipped more than one build that day for different hardware revisions — either works.