Description: Using data from the Health & Retirement Study [HRS], a two-part medical claim prediction model is estimated for a cohort of survey respondents approaching Medicare-eligibility age. A High Deductible Health Plan [HDHP] with a companion Health Savings Account [HSA] is applied to simulated claims streams to model the build-up of HSA assets over the near-retirement years. Results show that the HSA is a grossly inadequate savings vehicle to provide for retiree medical care expenses at age 65. Moreover, HSA adequacy worsens exponentially with diminishing health status. Based on this simulation, it is apparent that Baby Boomers cannot adequately provide for the costs of medical care in retirement using HSAs exclusively.