The Swedish Defence Research Agency has, commissioned by the Swedish Radiation Protection Authority, measured gamma radiation from particles sampled on filters in the stratosphere. The sampling was performed by the military aircraft Lansen during four sessions at 12 500 m above Gotland the 21/12-04 and the 24/1-05. A total of 19 filters from 16 different pods have been analyzed regarding gamma radiation. The isotopes detected were Be-7 and Cs-137. Be-7 is created in the stratosphere, and the measured concentration was approximately 100 times higher than at ground level at the same time. The measured Cs-137 was not from the surroundings but from previous contamination of the pods.