Job duration patterns are examined for evidence of health insurance-related job lock among chronically ill workers or workers whose family member is chronically ill. Using Cox proportional hazard models to indicate the effect of health insurance and health status on workers' job duration we allow for more general insurance effects than that shown in the existing literature. Data for workers in Indiana predating the Health Insurance Portability and Accountability Act (HIPAA) are used to examine the potential effect of HIPAA on job mobility. Among the workers in this sample who relied on their employer for coverage, chronic illness reduced job mobility by about 40 percent as compared with otherwise similar workers who did not rely on their employer for coverage. Results reported here identify previously under-appreciated job lock among chronically ill workers and workers whose family member is chronically ill, clarify how one best researches job lock, and indicate the potential effect of policies aimed at alleviating job lock and promoting inter-employer worker mobility. © 2001 by the Association for Public Policy Analysis and Management.