For Medicare and HSAs, there are a few restrictions. To contribute to an HSA, a person must be enrolled in an HDHP. However, when an HSA owner’s Medicare coverage begins, he or she can no longer contribute to the HSA. Keep in mind, though, the HSA balance is available for other out-of-pocket medical expenses.
In order to continue making HSA contributions, the HSA owner should not apply for Medicare, Social Security or Railroad Retirement Board benefits.