Background. Millions of Americans are intermittently uninsured. The health consequences of this are not known. Setting. National survey. Participants. Six thousand seventy-two participants in the Health and Retirement Study (HRS) age 51 to 61 years old with private insurance in 1992. Measurements. Loss of insurance coverage between 1992 and 1992 and development of a major decline in overall health or a new physical difficulty between 1994 and 1996. Results. In 1994, 5768 (95.0%) people continued to have private insurance, 229 (3.8%) reported having lost all insurance, and 75 (1.2%) converted to having only public insurance. Over the subsequent 2 years (1994-1996), the risk for a major decline in overall health was 15.6% for those who lost all insurance versus 7.2% for those with continuous private insurance (P