An integrated vertical column abundance of 1.5¿4¿10+14 molec.cm-2 of HOCl has been inferred from high resolution infrared solar spectra measured by the JPL MkIV interferometer from the NASA DC-8 aircraft during flights over Antarctica in September 1987. This result was obtained by averaging spectra recorded at different times, dates and locations, but may be considered a mid-morning measurement at a solar zenith angle of 88.2 degrees from 79¿S, 83¿E on September 20. This result poses an important constraint on the amount of HOx inside the Antarctic winter vortex and on the contribution of the HOCl catalytic cycle to the observed spring-time ozone depletion. ¿ American Geophysical Union 1989