U.S. Office of Personnel Management - Ensuring the Federal Government has an effective civilian workforce

If there isn't a valid designation on file when you die, benefits are payable in this order:

First: to your widow or widower

Second: if none, to your child or children in equal shares, with the share of any deceased child distributed among that child's descendants

Third: if none, to your parents in equal shares or the entire amount to your surviving parent

Fourth: if none, to the executor or administrator of your estate

Fifth: if none, to your next of kin under the laws of the State where you lived at the time of your death.

BE SURE to read the specific instructions on each designation form before designating beneficiarites.