Acquired obstructions of the lower urinary tract in children are uncommon. They can be divided into intrinsic and extrinsic lesions, and have a very varied etiology. Several illustrative cases are reported, such as traumatic and infectious strictures, meatal stenosis, benign and malignant tumors, fused labia, and epidermolysis bullosa. Many of these lesions have distinct radiographical features, best demonstrated by micturating cystourethrograms.