"Dual eligibles" is the term for the 6.4 million low-income, elderly, and disabled Americans who are enrolled in both Medicare and Medicaid. With home- and community-based services waivers allowed under Section 1915(c) of the Social Security Act, many of these individuals are able to live in a home or community setting, thereby avoiding institutionalization. Surveying Maryland's 3,180 dual eligibles who are enrolled in home- and community-based waiver programs, the author finds that the end-of-2005 transfer of prescription drug coverage from Medicaid to Medicare under the Medicare Modernization Act of 2003 could put these beneficiaries in jeopardy. Maryland's experience is likely to be typical of what other states will face. The author recommends a number of federal policy remedies, among them allowing 90-day prescriptions, using open or shared formularies, and lengthening the enrollment period.