How do I sign up for Medicare Part B if I already have Part A?

If you have Medicare Part A, but you did not enroll in Medicare Part B during your Initial Enrollment Period (IEP), you may sign up during the General Enrollment Period (GEP), or you may qualify for a Special Enrollment Period (SEP).

The annual GEP runs from January 1 to March 31, with coverage starting the month after you enroll. You may have to pay a late enrollment penalty for not signing up when you were first eligible.

Those with group health plan coverage through an employer or spouse may qualify for an SEP. If you qualify for an SEP, you can apply online at Apply for Medicare Part B Online during a Special Enrollment Period.

You can also fax or mail your completed Application for Enrollment in Medicare – Part B (CMS-40B) and the Request for Employment Information (CMS-L564) enrollment forms and evidence of employment to your local Social Security office. If you have questions, please contact Social Security at 1-800-772-1213 (TTY 1-800-325-0778).

Note: When completing the forms CMS-40B and CMS-L564:

• State “I want Part B coverage to begin (MM/YY)” in the remarks section of the CMS-40B form or online application.
• If your employer is unable to complete Section B, please complete that portion as best as you can on behalf of your employer without your employer's signature.
• Also submit one of the following forms of secondary evidence:
  • Income tax returns that show health insurance premiums paid.
  • W-2s reflecting pre-tax medical contributions.
  • Pay stubs that reflect health insurance premium deductions.
  • Health insurance cards with a policy effective date.
  • Explanations of benefits paid by the GHP or LGHP.
  • Statements or receipts that reflect payment of health insurance premiums.

  For more information go to our Medicare Benefits page.