Topic: wil halo 3 odst multiplayer conect with halo 3 multi?

i have halo 3, but can you play people with odst?

If they're using the second disc that comes with ODST - the one with all the Halo 3 multiplayer maps - then yes, you can play Matchmaking with them, but not the ODST or Halo 3 story/campaign modes.

gotcha