Cervical lymphadenopathy is a common problem in children. The condition most commonly represents a transient response to a benign local or generalized infection, but occasionally it might herald the presence of a more serious disorder. Acute bilateral cervical lymphadenopathy usually is caused by a viral upper respiratory tract infection or streptococcal pharyngitis. Acute unilateral cervical lymphadenitis is caused by streptococcal or staphylococcal infection in 40% to 80% of cases. The most common causes of subacute or chronic lymphadenitis are cat scratch disease, mycobacterial infection, and toxoplasmosis. Supraclavicular or posterior cervical lymphadenopathy carries a much higher risk for malignancies than does anterior cervical lymphadenopathy. Generalized lymphadenopathy is often caused by a viral infection, and less frequently by malignancies, collagen vascular diseases, and medications. Laboratory tests are not necessary in the majority of children with cervical lymphadenopathy. Most cases of lymphadenopathy are self-limited and require no treatment. The treatment of acute bacterial cervical lymphadenitis without a known primary source should provide adequate coverage for both Staphylococcus aureus and group A beta hemolytic streptococci.