Retention cysts arising from obstructed Cowper's ducts are rare lesions of the anterior urethra. Five cases are reported, 3 in male infacts and 2 in young boys. In children and adults the cysts may cause dysuria, urinary frequency, or urinary retention. The etiology of Cowper's duct cysts remains uncertain, but both congenital and acquired cysts have been described. The radiographic findings are characteristic: a smooth, rounded filling defect is seen on the ventral wall of the proximal bulbous urethra during voiding cystourethrography. After fulguration of the cyst, urethrography may reveal reflux into a dilated Cowper's duct.