No. Enrollment in any Medicare program makes you ineligible for HSA contributions. You will be able to make a partial year HSA contribution in the year you begin Medicare. This amount will be based on the number of months you were eligible prior to the Medicare enrollment. For example, a Medicare enrollment starting October 1 2017 will still allow you to contribute nine months (Jan thru Sept) of the annual amount. You can add this amount anytime before April 15, 2018 when you must file tax forms.