What documents do I need to travel to Mexico?

I am traveling to Guadalajara, Mexico. What documents do I need? Other than my Permanent Resident Card.

Are you holding the US Permanent Resident Card (US Green Card)? If so, you don't need to obtain a tourist VISA (as long as your Permanent Resident Card is not expired), you are allowed to stay in Mexico up to 180 days. All you need is to carry your Passport and Permanent Resident Card with you.

For further information, please check this page:
http://travel.state.gov/travel/cbpmc/cbpmc_2223.html