Abstract : Blunt probes for measuring polar electrical conductivity have been flown on the recent series of STRATCOM balloon experiments. Although the instrument has primarily been employed with rocket systems, it has been found useful for studying ionization processes in the stratosphere when flown on balloon platforms. The three most recent balloon flights floated in different altitude regions of the stratosphere. These made possible the study of conductivity and its associated variability at relatively fixed altitudes of 48 km, 28 km, and 39 km. Another function of the blunt probe was to measure the ionization effects caused by an ultraviolet lamp which was operated for designated time periods during the balloon flights. In conjunction with the 28 km balloon flight, a rocket-launched parachute-borne blunt probe experiment was conducted nearby, thus providing an altitude profile for electrical conductivity to supplement the data obtained from the balloon-borne instrument. General agreement was observed between the rocket data and the corresponding balloon measurements.