Creutzfeldt-Jakob disease (CJD) is an infectious prion disease caused by the accumulation of misfolded prion proteins in the central nervous system. It is associated cognitive impairment and ataxia, and results in death within several months after the onset. CJD is subdivided into sporadic, genetic, and acquired types according to the phenotype, epidemiological features, and pathogenesis. Laboratory diagnosis of CJD offers the advantage of being autopsy-free and is essential for accurate diagnosis of the disease along with assessment of clinical symptoms and electroencephalography. In addition, since the incidence of CJD is increasing worldwide, including in the Republic of Korea, the importance of laboratory diagnosis of the disease is also increasing. The 14-3-3 protein analysis, real-time quaking-induced conversion (RT-QuIC), prion protein (PRNP) gene mutation analysis are mainly used to diagnose CJD. Since each of these diagnostic tests has different interpretations and limitations, combined analysis is essential for the accurate diagnosis and classification of CJD. For efficient disease management, a diagnosis accompanied by simultaneous multilateral analysis using various laboratory diagnostics is indispensable in patients with suspected CJD.