I have been issued an immigrant visa but will not be able to travel to the US before the visa expires.  Can I still use my visa to immigrate to the US?  What should I do?
You cannot use an expired visa to travel to the US, although it may be possible for you to apply for a new visa.  You should return your immigrant visa package and passport to visa center, giving us a statement why you have been unable to use the visa.  We will be able to cancel the visa we originally issued in your passport.
 
If you wish to immigrate to the US at a later time, you will have to reapply and pay a new application fee.   Your petition will still be valid.