Column abundances of OClO were measured during the Airborne Arctic Stratospheric Expedition from January 6 to February 9, 1989 by near UV absorption spectroscopy. OClO was detected during AASE inside the vortex and at the edge of the vortex with column abundances of 3--10¿1012 cm-2 under twilight conditions and up to 1¿1014 cm-2 during the night. For comparison, in the Antarctic winter nighttime column abundances of OClO ranged from 1--2.5¿1014 cm-2, while those at mid-latitudes were below the detection limit, i.e., by at least a factor of 10 lower (Solomon et al., 1988). The measurements are broadly consistent with observed BrO column abundances and chemical model calculations. ¿ American Geophysical Union 1990