Abstract: Cigarettes are tested with air streams which are caused to pass lengthwise through the fillers while the cigarettes move sideways past a testing station. One or two stationary chambers for air at subatmospheric or superatmospheric pressure are mounted at the testing station so that the ends of cigarettes which are being tested extend into the chamber or chambers. The air pressure in the chamber or chambers equals or approximates the pressure of air streams at the respective ends of the wrappers of cigarettes so that air in the chamber or chambers prevents the streams from communicating with the atmosphere during testing. The streams are monitored for changes in pressure. Such changes are indicative of defects of cigarettes and signals which are produced during monitoring are used to segregate defective cigarettes from satisfactory cigarettes.