This Issue Brief is designed to provide a basic understanding of the relationship of the Employee Retirement Income Security Act of 1974 (ERISA) to health plans. It is based, in part, on an Employee Benefit Research Institute-Education and Research Fund (EBRI-ERF) educational briefing held in March 1995. This report includes a section by Peter Schmidt of Arnold & Porter, a section about multiemployer plans written by Judy Mazo of The Segal Company; and a section about ERISA and state health reform written by Kala Ladenheim of the Intergovernmental Health Policy Project. Starting in the late 1980s, three trends converged to make ERISA a critical factor in state health reforms: increasingly comprehensive state health policy experimentation; changes in the makeup of the insurance market (including the rise in self-insurance and the growth of managed care); and increasingly expansive interpretations of ERISA by federal courts. The changing interpretations of ERISA's relationship to three categories of state health initiatives--insurance mandates, medical high risk pools, and uncompensated care pools--illustrate how these forces are playing out today. ERISA does have a very broad preemptive effect. Federal statutes do not need to say anything about preemption in order to preempt state law. For example, if there is a direct conflict, it would be quite clear under the Supremacy Clause [of the U.S. Constitution] that ERISA, or any federal statue, would preempt a directly conflicting state statute. States can indirectly regulate health care plans that provide benefits through insurance contracts by establishing the terms of the contract. And they also raise money by imposing premium taxes. But they cannot do the same with respect to self-funded plans. That is one of the factors that has caused a great rise in the number of self-funded plans. State regulation [of employee benefits] can create three kinds of problems: cost of taxes, fees, or other charges; cost of dealing with substantive, possibly inconsistent, benefit standards; and cost of identifying, understanding, and complying with the regulations themselves.