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.