MediKids Health Insurance Act of 2000 - Amends the Social Security Act to add a new title XXII (MediKids Program) under which an eligible individual born after December 31, 2001, who has not attained age 23 may enroll in the MediKids Program for entitlement to benefits specified by the Secretary of Health and Human Services (HHS). Includes among such benefits the following: (1) at least the same benefits available under Medicare parts A (Hospital Insurance) and B (Supplementary Medical Insurance) under SSA title XVIII; (2) early and periodic screening, diagnostic services, and treatment services under Medicaid (SSA title XIX); and (3) prescription drugs and biologicals. Provides for cost-sharing, a payment schedule for covered benefits, and a monthly MediKids premium and the means for payment of it. Provides for a reduction in premium for certain low-income families.

(Sec. 2) Creates in the Treasury the MediKids Trust Fund (Trust Fund) for collected premiums, appropriated amounts, and other revenues for use in funding the coverage provided under the MediKids Program and maintaining its financial solvency.

Authorizes the Secretary to implement a care coordination services program including specified elements under which eligible individuals may elect to have health care services covered under new SSA title XXII managed and coordinated by a designated care coordinator.

Sets forth administration and miscellaneous provisions applicable to new SSA title XXII, including provisions for coordination with Medicaid and SSA title XXI (Children's Health Insurance) and the maintenance of Medicaid eligibility and benefits for children.

Amends SSA title XVIII to increase the membership of the Medicare Payment Advisory Commission from 17 to 19 members, with the initial terms of additional members staggered.

(Sec. 3) Amends the Internal Revenue Code to: (1) impose a MediKids premium tax in the case of any taxpayer required to pay a premium under the MediKids Program for an eligible individual; and (2) provide for a refundable tax credit for cost-sharing expenses under the MediKids Program.

(Sec. 5) Mandates deposit in the Treasury of any amounts: (1) recovered by the United States in the civil action brought on September 22, 1999, under the Medical Care Recovery Act and other specified provisions of Federal law in the U.S. District Court for the District of Columbia against the tobacco industry and associated parties; and (2) attributable to expenditures of HHS for tobacco-related illnesses.

(Sec. 6) Directs the Secretary of the Treasury to propose a gradual schedule of progressive tax changes to fund the MediKids program as the number of enrollees grows in the out-years.