A provider, doctor or hospital that does not sign a contract to participate in a health plan, usually which requires reduced rates from the provider. In the Medicare Program, this refers to providers who are therefore not obligated to accept assignment on all Medicare claims. In commercial plans, non-participating providers are also called out of network providers or out of plan providers. If a beneficiary receives service from an out of network provider, the health plan (other than Medicare) will pay for the service at a reduced rate or will not pay at all.