This final rule implements section 8012(a) of Pub. L. 101-239 which, effective October 1, 1990, changed the definition of the term ``eligible spouse'' as it is used in the supplemental security income (SSI) program. Under the former definition of ``eligible spouse,'' members of an SSI eligible couple who began living apart could not be treated as individuals for SSI eligibility and payment purposes during the first 6 months following the month in which they began living apart. The statutory change eliminated the 6-month waiting period. The final rule revises the definition of ``eligible spouse'' contained in the regulations as well as makes a number of other conforming changes. Finally, the rule eliminates provisions in the regulations pertaining to eligible couples living apart.