Strengthening Social Security and Medicare Act of 1999

Strengthening Social Security and Medicare Act of 1999 - Amends title II (Old Age, Survivors, and Disability Insurance) of the Social Security Act (SSA) to make additional appropriations, in amounts prescribed by a specified formula, and allocated between the Federal Old-Age and Survivors Insurance Trust Fund and the Federal Disability Insurance Trust Fund (Trust Funds), through FY 2016 to assure that the interest savings on the public debt achieved as a result of Social Security surpluses from 2000 to 2015 are dedicated to Social Security solvency.

Amends the Congressional Budget Act of 1974 to make it out of order in Congress to consider any budget resolution that would: (1) set forth an on-budget deficit for any fiscal year; or (2) decrease the on-budget surplus below a level of Medicare surplus reserve determined according to a certain formula, except for any portion of such reserve appropriated in new amounts for Medicare prescription drug benefits, or to the Medicare Hospital Insurance Trust Fund.

Amends the Balanced Budget and Emergency Deficit Control Act of 1985 (Gramm- Rudman-Hollings Act) to extend: (1) discretionary spending limits in specified amounts; (2) the pay-as-you-go requirement; (3) the Act itself; and (4) the Social Security firewall.

Declares that any legislation that would reduce, reverse, or repeal the transfers to the Trust Funds made by this Act shall not be counted on the pay-as-you-go scorecard and shall not be included in any pay- as-you-go estimates of the Congressional Budget Office or the Office of Management and Budget under the Gramm-Rudman-Hollings Act.