Thyroid nodules in childhood and adolescence are less prevalent but more often malignant than in adulthood. Malignant nodules are predominantly papillary cancers; benign nodules are mostly solid colloid nodules/adenomas, but can be cystic or due lymphocytic thyroiditis. Previous neck irradiation (nowadays mostly encountered in childhood cancer survivors) is a clear risk factor for developing nodules. Neck irradiation for childhood Hodgkin's disease has a relative risk of 27 for the development of thyroid nodules. Female sex, a thyroid radiation dose>or=2500 cGy, and time since irradiation of >or=10 yr are independent risk factors. This subset of patients deserves long-term follow-up. The diagnostic steps for thyroid nodules in children and adolescents are not different from those in adults. First, history and physical examination should identify risk factors for malignancy of the nodule. Second, thyroid function should be assessed by serum TSH, followed by a thyroid scan in the case of a suppressed TSH. Serum calcitonin might be measured if there is suspicion of medullary thyroid carcinoma (e.g. a family history of MEN). Thyroid ultrasound is useful, especially in guidance of FNAC for optimal results, but presently should not be used for final decisions on the benign or malignant nature of the nodule. FNAC has the highest diagnostic accuracy in recognizing malignant nodules and should be applied in all nodules>or=1 cm and in nodules<1 cm only if there is suspicion for cancer (e.g. by ultrasound characteristics). Surgery is the most cost-effective treatment option for thyroid nodules, solving the problem fast. Levothyroxine treatment has a low efficacy. Experience with other treatment options like ethanol injection or laser therapy is still limited.