If you are still working, the size of the company you work for will determine whether you still need to enroll into Medicare.
Companies with 20 or more employees will provide primary coverage and allow individuals to be fill any gaps with Medicare. This includes your spouse if they have insurance through your employer. Individuals are not required to sign up at age 65 and no late-enrollment penalty will apply. If an individual or spouse leaves his/her job and loses employer insurance coverage, then enrollment is required and a late enrollment fee will apply after 8 months.
When an Individual is Required to Sign Up for Medicare
At times, individuals over 65 who are satisfied with their employer's insurance coverage may opt to delay enrollment for Medicare Part B. However, individuals over 65 that still work in companies of less than 20 people must enroll in Medicare Part A and Part B. Occasionally these smaller employers will negotiate terms with insurers to maintain primary employee coverage. If this happens, be sure to obtain documentation from your employer if they have chosen to negotiate terms on your behalf.
Those who receive Social Security benefits are automatically enrolled into Medicare and cannot delay enrollment for Part A, regardless of employment status.