With Medicare, the term “network” describes the network of doctors and healthcare providers offered by a Medicare plan. The two main network types are HMO and PPO.

Some doctors and providers are “in-network” (and thus covered under the in-network portion of the plan) while others are “out-of-network” (and thus either not covered or covered at different cost-sharing amounts).[1][2]

Generally speaking, Health Maintenance Organization (HMO) plans have more restricted networks and require referrals, while Preferred Provider Organization (PPO) plans allow you to go outside-of-network for a fee and may not require referrals.

To learn more about network types, see Medicare Advantage Plan Types.


  1. Health Maintenance Organization (HMO). Medicare.Gov.
  2. Preferred Provider Organization (PPO). Medicare.Gov.