Measurements of stratospheric HF have been made by the JPL MkIV interferometer during high-altitude balloon flights. Infrared solar absorption spectra were acquired near 35¿ N at altitudes between local tropopause and 38 km. Volume mixing ratio profiles of HF derived from 4 flights (1990--93), in conjunction with simultaneously observed N2O profiles, indicate an average rate of HF increase of (5.5¿0.3)% per year, in agreement with time-dependent, two-dimensional model simulations (6% per year) and ATMOS measurements. ¿American Geophysical Union 1995