A microprocessor-controlled device for the spiking of cigarettes with variable amounts of radiolabelled material is described. Cigarettes can be spiked at rates in excess of 100/min, compared with the very slow manual methods in existence. The deposition of the radiolabelled material ([16,17-14C]dotriacontane) is very reproducible with a coefficient of variation of around 3 %. The device is capable of injecting cigarettes of various physical configurations, and of producing variable distributions of the radiolabelled material along the tobacco rod.