If you are traveling from the u.s. to mexico by plane, yes, you need a mexican passport.

You can go to any mexican consulate and present your birth certificate and photo id and they’ll issue you a mexican passport.

If you FLY to Mexico, technically , you need a passport, but in real life, as a Mexican citizen, you can fly without one. BUT, you need a passport to fly back. You cannot get a U.S. passport as you are not a citizen, so you need to go to the nearest Mexican consulate and apply for a Mexican passport. As a permanent resident of the U.S. you are responsible to keep a current passport from your home country at all times. Is your green card current? Be sure it is before you leave the U.S. If you are travelling by LAND, passports are not yet needed, but wil be in a few months.

You definitely need a pasport anytime you get out of the country and go to another country regardless of your nationality. So your a permanent resident of the U.S but are you also a mexican citizen? If you are are also a Mexican citizen then you should be carrying a mexican pasport. Don’t forget to bring your Perm. Card also you need to show that as well.

You need a passport to come back into the U.S. as of yesterday. alternately, a driver’s license and a CERTIFIED COPY of your birth cirtificate will work.. but the passport is easier… THIS JUST HAPPENED so any information that says otherwise… is old information.