I might have posted this question before, but still confused about the answer. My parents have the immigrant visa stamp in their passport. On it is says"upon endorsement serves as temporary evidence of permanent residence I-155 for one year" however there is a visa expiration date on it he stamp as well that is expired this june. The visa is endorsed upon my parents entry to the us on December 2006. My problem is that it hasn't still been a year since the visa is endorsed, but that expiration date on the visa has passed. Can my parent still travel abroad and come back to US?
Thanks

They should have green-card by now. The visa it self is void upon first use, the I-551 stamp makes the passport act as a temp green-card until you have the actual card in hand, after that the stamp in passport makes no difference.

When traveling abroad, just take Passport, and Green-card, the passport is for traveling, and the green-card is used to re-enter the USA and is shown to the officer at the POE, no visa required unless the trip lasts more than 2 years.

Also if trip is longer than 1 year a re-entry permit (I-131) is needed as well as green-card to re-enter the country.

The problem is that they haven't yet received their green card. I callled the USCIS and they said they can travell with the stamp as long as it hasn't been a year since its endorsement. But I want to make sure, because sometimes the costomer service just says something that doesnt make sense.

They are correct, the temp I-551 stamp is considered to be valid for 1 year from issuance.

I would also do an info pass appointment to find out what happened to the cards, perhaps they were sent to a wrong address.