We have obtained a statistically significant measurement of H2O2 in the stratosphere. The results were obtained from the 112.19 cm-1 RQ5 branch of the torsional-rotational spectrum with a remote-sensing far-infrared Fourier transform spectrometer during the Balloon Intercomparison Campaign (BIC-2), on June 20, 1983. The concentration above the balloon gondola is unexpectedly large, corresponding to 0.68 ¿ 0.21 parts per billion by volume (ppbv) at an effective altitude of 38.3 km. Below the gondola altitude the concentration of H2O2 is slightly less than expected from the model predictions at 33.2 km (0.19 ¿ 0.05 ppbv) and significantly less than expected at 29.3 km (0.08 ¿ 0.03 ppbv). ¿American Geophysical Union 1987