The Department of Laboratory Medicine performs and interprets various laboratory tests for disease diagnosis and evaluation of prognosis and treatment response based on the laboratory analysis of biomolecular and cellular components from all kinds of samples derived from patients. Our department is subdivided into individual laboratories for diagnostic hematology, clinical chemistry, clinical microbiology, transfusion medicine, diagnostic immunology, cytogenetics, and molecular diagnostics & genetics. By using total laboratory automation (TLA), 24-hour rapid testing systems, next-generation sequencing (NGS), and thorough administration of quality control activities, accurate and precise test results are provided promptly to the medical staff. Our department also participates in various domestic and international accreditation programs such as the CAP survey. By introducing, applying, and developing new in vitro diagnostics technologies and new biomarkers, the laboratory medicine takes a leading role in the tailored medicine in the 21st century.