Сhronic inflammatory demyelinating polyneuropathy (CIDP) is the most prevalent acquired dysimmune neuropathy with clinical picture of symmetric motor and sensory disturbances. Since the first description of CIDP, many atypical variants have been described, which may reach up to 50% of cases. Diagnosis of atypical CIDP may be challenging due to different clinical presentation and treatment response. Current researches improve our knowledge about dysimmune neuropathies and highlight the importance of its classification. Nowadays CIDP is considered as a spectrum of disorders rather than a separate disease entity. Up to date, more than 15 diagnostic criteria have been proposed reflecting the complexity of СIDP diagnosis. Many polyneuropathies may mimic CIDP, therefore CIDP is frequently a diagnosis of exclusion. The key diagnostic instrument is electroneuromyography; however, the issues related to results misinterpretation and some technical aspects are the most important in CIDP misdiagnosis. Supportive instrumental and laboratory methods have variable sensitivity and specificity, making challenging CIDP diagnosis, especially its atypical forms. The importance of an early and accurate diagnosis of CIDP is supported by an effective pathogenic treatment, which affects the patient's prognosis and level of disability.