Scenario Who pays first You’re 65 or older and have retiree insurance (insurance from former employment) Medicare You’re 65 or older, have group health plan coverage based on your or your spouse’s current employment and the employer has 20 or more employees Your group health plan You’re 65 or older, have group health plan coverage based on your or your spouse’s current employment and the employer has less than 20 employees Medicare You’re under 65 and disabled, have group health plan coverage based on your or a family member’s current employment and the employer has 100 or more employees Your group health plan You’re under 65 and disabled, have group health plan coverage based on your or a family member’s current employment and the employer has less than 100 employees Medicare