OBJECTIVES: Health insurance instability is a prevalent phenomenon in the United States. A large number of studies provide evidence that health insurance instability affects healthcare utilization. However, none of the studies have looked at the specific effect of prescription drug insurance instability on the use of drugs for chronic conditions like hyperlipidemia. Therefore, the objective of this study was to describe the association between prescription drug insurance instability and the access of anti-hyperlipidemics among people aged 18 to 64 years. METHODS: The data for this study was obtained from the 2000 Medical Expenditure Panel Survey, a nationally representative survey of healthcare use and spending in the U.S. civilian, non-institutionalized population. Complete prescription drug coverage data was obtained by combining data from the private prescription drug insurance variable and several health insurance variables representing programs that frequently, or nearly always, include prescription coverage. Medical Conditions (MEPS:HC-052) and Prescribed Medicines (MEPS:HC-015A) files were used to generate information about this disease condition and events of anti-hyperlipidemic access respectively. RESULTS: The 2000 MEPS contained 14,223 respondents between the ages 18-64 with sufficient insurance information throughout the year. Among this age group, 740 people reported to have hyperlipidemia whereas only 230(31.1%) reported purchasing any anti- hyperlipidemics. Among the people who had purchased any anti-hyperlipidemics during the year 2000, 183 (79.57%), 35 (15.22%) and 12 (5.22%) had continuous drug insurance, unstable insurance and no drug insurance throughout the year respectively. The association between drug insurance statuses and acquisition of any lipid lowering agent was statistically significant at p <0.05 after controlling for demographics, socio-economic and employment characteristics. CONCLUSION: As in previous studies of insurance instability, there appears to be an association between anti-hyperlipidemic access and prescription insurance status of an individual. Similar studies are required for other chronic conditions like hypertension and diabetes.