Permanent residents are free to travel outside the United States, temporary or brief travel for less than 6 months a year usually does not affect your permanent resident status. But if you are planning to remain outside the U.S. for more than 1 year, but less than 2 years, you should apply for a reentry permit so you don't lose your permanent resident status.

Leaving the U.S. for more than 1 year creates an assumption that you did not intend to make the United States your permanent home. If it is determined that you do not have strong ties with the U.S., you can be found to have abandoned your permanent resident status. In order to avoid this situation it is advisable to apply for reentry permit.

In general, reentry permit does not relieve you of any of the requirements of U.S. immigration laws. It does not guarantee entry into the United States upon your return as you must first be determined to be admissible. However, it will assist you in establishing your intention to permanently reside in the United States. Obtaining a reentry permit prior to leaving the United States allows a permanent or conditional permanent resident to apply for admission into the United States during the permit’s validity without the need to obtain a Returning Resident visa from a U.S. Embassy or Consulate abroad.

You must be physically present in the United States when you file the Re-entry Permit application. After filing your application for a reentry permit, USCIS will inform you in writing when to go to your local Application Support Center (ASC) for your biometrics appointment. Departure from the United States before a decision is made on an application for a Re-entry Permit usually does not affect the application. However, where biometric collection is required and the applicant departs the United States before the biometrics are collected, the application may be denied.

Generally, a Re-entry Permit issued to a permanent resident shall be valid for 2 years from the date of issuance. A Re-entry Permit may not be extended.

If you were unable to return to the United States for reasons beyond your control within the travel validity period of the Permanent Resident Card (Green Card), or the Reentry Permit you can apply for Returning Resident visa (SB-1) at the nearest consulate.

To qualify for Returning Resident Status, you must show:

• That you were a lawful permanent resident when you departed the United States,
• That when you departed you intended to return to the United States and have maintained this intent,
• That you are returning from a temporary visit abroad and, if the stay was protracted, it was caused by reasons beyond your control and for which you were not responsible, and
• That you are eligible for the immigrant visa in all other respects.

The counselor officer will conduct a visa interview to determine whether you are eligible for Returning Resident visa. The application will be approved if you provide a consulate with persuasive evidence demonstrating your inability to come back to the U.S. for the reasons beyond your control. For example, taking care of your sick parent who lives abroad for more then a year is not considered a valid reason to apply for a Returning Resident visa. This decision is under your total control and you could have came back to the U.S. on time in order to keep your permanent resident status. However, delivering the baby abroad and subsequent overstaying due to doctor’s recommendation is something that happened beyond your control. In this situation you can receive a visa upon providing medical records evidencing your necessity to stay abroad under doctor’s care. Moreover, you still will be required to show the proof of retaining the U.S. as a primary residence (filing taxes in the U.S., having house in the U.S., paying off car’s loan and so on).

Even though your application for Returning Resident visa is approved, you still have to go through entire immigration process all over again (paying fee, going through medical examination, submitting immigrant petition). You must apply for Returning Resident visa within 6 months of getting approval for Returning Resident.

If your application is denied, you will need to file for green card on the same basis by which you immigrated originally. For example, your U.S. relative or U.S. employer will need to file an immigration petition on your behalf again. Once your immigration petition is approved, you can apply for immigrant visa and enter the U.S. again.