Fairness for Beneficiaries Act of 2013 - Amends title XVIII (Medicare) of the Social Security Act to revise requirements for Medicare coverage for extended care services which are not post-hospital extended care services (that is, without regard to the requirement for a 3-day prior hospitalization).

Limits such coverage to extended care services in a skilled nursing facility (SNF), but only if, before the individual is admitted to the SNF, a physician or other qualified health care practitioner determines and certifies that extended care services for the individual are medically necessary.