You can choose to keep Medicare Part A and B and obtain part D, or apply for part C (see Below on differences). Medicare Part A will give you: Hospital CareSkilled Nursing Facility CareNursing Home CareHospiceHome Health ServicesMedicare Part B will give you: Clinical Research Ambulance ServicesDurable Medical Equipment Mental healthIn Patient/Out Patient HospitalizationGetting a second Opinion before surgeryLimited Out Patient Surgery PrescriptionIf you choose to keep Medicare without enrolling in Part C (HMO), Medicare will cover 80% of all hospital and medical fees, and you will be responsible in paying the remaining 20%.You have the option of enrolling into Medicare Part C. Medicare Part C is an HMO plan and will not have a set 80/20% rule, but will have certain co-pays, and/or deductible for certain services as most HMO plans do. Most Medicare Part C's are accepted at hospitals and doctor's offices, but you should check with your Primary Care doctor to see which ones (s)he accepts. Medicare Part D is included in Part C, so it is not necessary to obtain a separate Part D Plan. This is a popular choice amongst those who are pretty healthy, there are typically no monthly insurance premiums and there are many ancillary benefits such as Chiropractic/Acupuncture benefits, Hearing and Vision service benefits, and even free gym memberships (Silver Sneakers or Nifty after Fifty) included in the Part C plan. (Benefits and services vary among state, and region as well as insurance cmpany and plans). Medicare Part D is Mandatory for anyone receiving Medicare. Part D covers your prescription drugs, and typically costs around $15-25/month. You must enroll in a Part D plan even if you are currently not being prescribed medication, and will be penalized for every month not enrolled. Again, you can get this amount waived by enrolling in a Part C plan. There are other Medicare plans such as Supplemental Insurances (Medicare part F) that you can enroll in as well. My advice to is contact a local Medicare Insurance Agent to discuss which type of plan may be best suited for you.