Health Maintenance Organization. HMO’s are popular health benefit programs in which you’ll pay monthly premiums in return for managed coverage for your checkups, hospital stays, doctors’ visits, surgery, emergency care, preventive care, lab tests, and X-rays. If you join an HMO, you will have to select what’s called a “Primary Care Physician” who will be responsible for coordinating your healthcare and making any referrals to specialists that you require. You’ll also have to use doctors, hospitals and clinics who are members of your HMO plan’s network.