Medicare supplement and Medicare select insurance companies must make coverage available to all new Medicare enrollees, regardless of age, for 6 months beginning with the date they enroll in Medicare Part B. This 6-month period is often called the open-enrollment period.
During the open enrollment period insurance companies may not deny or condition the issuance or effectiveness of a policy on your health status, claims experience, receipt of health care, or medical condition and may not apply a higher rate for tobacco use. The policy may still have waiting periods before preexisting health conditions are covered.
In addition, if you are under age 65 and eligible for Medicare due to disability or end stage renal disease are entitled to a 6-month open enrollment upon reaching age 65.