Health maintenance organizations are prepaid health plans. As an HMO member, you pay a monthly premium. In exchange, the HMO provides insurance coverage for you and your family, including doctors' visits, hospital stays, emergency care, surgery, lab tests, x-rays, and therapy. {doctor examining x-ray}

You arrange for this care either directly through the HMO's own group practice and/or through doctors and other health care professionals under contract with the HMO -- the HMO network. Usually, your choices of doctors and hospitals are limited to those that have agreements with the HMO to provide care. However, exceptions are made in emergencies or when medically necessary.

There may be a small co-payment for each office visit, such as $15-$25 for a doctor's visit or $50-$100 for hospital emergency room treatment. Your total medical costs will likely be lower and more predictable in an HMO than with fee-for-service insurance.

• More about HMOs

• Questions to ask about an HMO

• PPO (Preferred Provider Organization)

• POS (Point-of-Service)