A discharge fast flow system with mass spectrometric detection was used to determine the rate constant of the title reaction to be k(1)=(1.3¿0.2)¿10-13 cm3 molecule-1 s-1. This experimental value is roughly a factor of 20 higher than previously recommended. It is suggested that the title reaction should be considered as a removal process in modeling stratospheric HOCl. ¿ American Geophysical Union 1992