Percutaneous insertion of a radiopaque marker is an important technique used in radiotherapy planning for both external-beam and brachytherapy. It is of particular importance in the oral cavity. We describe the construction and use of a simple inserter for 'cold' gold seeds manufactured from a commercially available Becton Dickinson Brand 5-mL disposable syringe and a Becton Dickinson Brand 18 G 1 1/2 TW (1.25 x 38 mm) hypodermic needle.