Medicare Physician Workforce Improvement Act of 1999 - Amends title XVIII (Medicare) of the Social Security Act to revise the rules for determining the number of full-time equivalent residents in an approved medical residency training program for purposes of determining payments for direct graduate medical education (GME) costs to provide that a resident enrolled in a fellowship in geriatric medicine or geriatric psychiatry within an approved medical residency training program be counted twice for the period such resident is enrolled in such fellowship (thereby doubling GME payments made to teaching hospitals for geriatric fellows). Caps the double payment to be provided for an approved medical residency training program to a maximum of 400 fellows per year.

Directs the Secretary of Health and Human Services to establish and conduct a limited number of demonstration projects to increase the number of certified geriatricians who are appropriately trained to provide items and services to beneficiaries under the Medicare program in a range of patient settings. Directs the Secretary to make annual reports to the Congress on such projects.