The aims of this study are to assess the real-world effectiveness of efgartigimod in treating chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), describe the "treatment journey" of participants with CIDP, and assess the utilization of health care services among adult participants with CIDP who initiate treatment with efgartigimod.

As this is a noninterventional study, treatment choices and decisions will be left to the discretion of participants and their physicians, according to the standard of care.

Each participant will be prospectively followed for up to 2 years from the date of initial administration of efgartigimod.

Inclusion Criteria:

• Aged ≥18 years at time of providing informed consent
• Diagnosed with CIDP
• Planned to be receiving efgartigimod treatment within the CIDP treatment label of efgartigimod in the participant's respective country
• Efgartigimod treatment-naïve at time of screening

Exclusion Criteria:

• Polyradiculoneuropathy due to any other cause(s)
• Current participation in any interventional clinical study at time of screening, or planned participation before initiation of efgartigimod

Adult CIDP participants considered to be initiating efgartigimod treatment per country-specific label for the treatment of CIDP