Prepaid group practice plan - A plan under which specified health services are rendered by participating physicians to an enrolled group of persons, with a fixed periodic payment made in advance by (or on behalf of) each person or family. If a health insurance carrier is involved, a contract to pay in advance for the full range of health services to which the insured is entitled under the terms of the health insurance contract. An HMO is an example of a prepaid group practice plan. .