Lymphadenopathy is a term which encompasses abnormality in size, consistency and number of lymph nodes. It occurs as a reaction of a lymph tissue to various external and internal antigens, during which lymphocyte and macrophage counts increase and the lymph node subsequently increases in size. The growth of a lymph node can also be the result of the infiltration of inflammatory cells (lymphadenitis), proliferation of malignant cells within the lymph node, metastatic infiltration and diseases of accumulation. A lymph node under the size of 1 cm is considered normal, with the exception of epitrochlear (0.5 cm) and inguinal (2 cm) lymph nodes. Lymph nodes can be enlarged in all regions, but most commonly enlarged nodes are of head and neck (55%), axillary (14%) and inguinal (5%) nodes. Lymphadenopathy, according to the number of affected regions, can be localized or generalized. According to biopsy, which is considered the gold standard in lymphadenopathy diagnostics, it can be benign or malignant. Benign lymphadenopathy mostly occurs because of various infections. Although it appears in all age groups, the highest incidence is in children. Benign lymph node usually grows rapidly and is tender, movable and of soft consistency. On the other hand, malignant lymphadenopathy mostly results from metastatic cancers and malignant lymphomas. It is more common in adults aged 50 or more. Malignant lymph node usually grows slowly, is non-tender, fixed and of firm consistency. Most patients presenting with lymphadenopathy have a self-limiting infection which is easy to diagnose and treat. However, there is also a group of patients where the cause of lymphadenopathy is not easily identifiable. The most important thing to establish in such patients is whether lymphadenopathy is a result of malignant disease. Lymph nodes greater than 1.5 cm in size, supraclavicular localization and generalized lymphadenopathy affecting more than 3 regions are usually unfavorable signs.