Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a demyelinating chronic neuropathy of immune origin whose diagnosis is based upon clinical, biological and electrophysiological data; previously critical to the diagnosis the nerve biopsy is now restricted to the rare situations where accurate diagnosis cannot be reached using these data alone. CIDP are mainly idiopathic, but a few associated diseases must be sought for as they require specific attention. Such associated diseases must particularly be discussed when the manifestations are severe or resistant to immunomodulating or immunosuppressive agents. Indeed, idiopathic CIDP are usually responsive to these treatments. The effectiveness of these treatments is limited by the importance of the secondary axonal loss. The dependence or the resistance may sometimes justify the association of several immunomodulating treatments. A single randomized controlled trial support the use of cytotoxic drugs and none with rituximab.