Fine needle aspiration biopsy (FNAB) guided by ultrasonography is routinely used to identify thyroid nodules prior to surgery. Although FNAB has great diagnostic accuracy and safety, it is limited by its relatively low diagnostic accuracy in follicular lesions, such as non-diagnostic or atypia of unclear significance (AUS)/follicular lesion of uncertain significance (FLUS). Additional diagnostic tests are required to overcome these challenges in evaluating thyroid nodules. Thyroid nodules can now be diagnosed with spring-activated single- or double-action needles following the introduction of core needle biopsy (CNB). CNB has the ability to address the limitations of FNAB by obtaining a sizeable tissue sample with more details on the histological structure supporting the capsule and fewer non-diagnostic effects brought on by the absence of follicular cells. Compared to repeated FNAB, CNB has been demonstrated to produce fewer ambiguous results, such as non-diagnostic or AUS/FLUS results. The Korean Endocrine Pathology Thyroid CNB Working Group issued its first set of guidelines for "Pathology Reporting of Thyroid Core Needle Biopsy" in 2015. In 2017, the Korean Society of Thyroid Radiology (KSThR) published "Core Needle Biopsy of Thyroid: 2016 Consensus Statement and Recommendations from the Korean Society of Thyroid Radiology". The main objectives of thyroid CNB are to detect individuals with thyroid illness who require surgery and to obtain a significant number of thyroid lesions with low morbidity.