CMS uses five different provider and supplier enrollment applications. In general, Part A providers are required to use the CMS-855A to enroll or update their enrollment information; Part B suppliers (except suppliers of Durable Medical Equipment, and Prosthetics, Orthotics, and Supplies (DMEPOS)) are required to use the CMS-855B to enroll or update their enrollment information; physicians and non-physician practitioners are required to use the CMS-855I to enroll or change their enrollment information; and DMEPOS suppliers are required to use the CMS-855S to enroll or update their enrollment information.  In addition to these four enrollment applications, individual practitioners who would like to reassign their benefits to an eligible provider or supplier or terminate an existing reassignment agreement would use the CMS-855R.

To ensure timely processing of your application, make certain to completely fill out the application and provide all required supporting documentation at the time of filing. Section 17 of the Medicare enrollment application lists the supporting documentation that you will need to submit with your enrollment application. Once you have completed the application, you should mail it to the Medicare contractor servicing your state.  A contractor can generally process your application within 60 days if you submit a complete application with all required supporting documentation.  It will take longer to be enrolled if you are a provider or supplier that requires a State survey or accreditation.  If you have any questions about the enrollment process, please contact your Medicare contractor.