For the United States, the Agreement applies only to the Retirement, Survivors, Disability, and Health Insurance (RSDHI) program’s Federal Insurance Contributions Act (FICA) taxes for employment and Self-Employment Contributions Act (SECA) taxes for self-employment, including the Medicare portion of these taxes, including the additional .09 percent applicable to high-earners. If an individual is exempt from U.S. Social Security coverage under this Agreement, the employee or employer's share of the FICA tax is not due as long as the exemption is in effect. A self-employed person is exempt from paying SECA taxes (equivalent to the employee and employer shares of the FICA tax) for any period the exemption is effective.

The U.S. laws to which the Agreement applies are Title II of the Social Security Act except section 226 (Medicare benefits), 226A (Medicare coverage for certain persons suffering from renal disease) and section 228 (special age-72 payments - Prouty benefits). Hospital insurance under Medicare has been excluded. Individuals to whom the Agreement applies, who qualify independently for Medicare hospital insurance benefits, would be entitled to receive such benefits.

For Portugal, the Agreement applies to social security coverage and taxes under the general social security system and to the special occupational systems, except for the system covering civil servants. This includes not only the taxes to finance the retirement, survivors, and long-term disability benefits, but also the taxes that finance other Portuguese programs, such as sickness (temporary disability), maternity, occupational injury and disease, unemployment, and family allowances. If the Agreement exempts a person from Portuguese social security coverage, they and their employer do not pay contributions under any of these programs.