Do legal residents of the US have to have a passport to travel to Mexico and back?

I know that US citizens have to have a passport now to get back into the US, but I was wondering if legal residents have to have a passport also. My dad is traveling to Mexico in a couple of weeks and he needs to know so he can get his passport.

The government is changing the laws depending how you are planning on crossing back and forth.

2007 - Flying into the US or Mexico a passport is required
2007 - Driving or by boat you will need a ceritified birth certificate and government issued photo ID. Residents of US need the Resident Alien card or Naturalization certificate with government issued photo ID.
2008 - ALL people will need a passport no matter how you travel.

i think u do i would tell ur dad to get it to be on the safe side with all the security going on in airports it would be the best thing to do .

If he is driving there he won't need it, but when you fly you need your birth certificate or passport. If he doesn't have a passport and is leaving in a few weeks, he better talk to him employer cause he's not going to get it in time. The gov. doesnt move very fast.

Yes, non-US citizens that are residents of the US need to take their passport with them to Mexico. Found this out the hard way when I had to drive to the house, get the passports, and bring it to the border checkpoint so that my wife and her sister could come across from Mexico.

Yes, now they do.

I think this doesn't go into effect until Jan 1.