From 1971 through April 1997 we have tracked the variation of stratospheric HCl using ground-based spectroscopic observations of the sun. This HCl is a tracer of free chlorine, the agent which catalytically destroys ozone. Our observations are dominated by a general increase in HCl by a factor between three and four, although since about 1990 the rate of increase may have slowed. ¿ 1997 American Geophysical Union