The diffusion and solubility of HCl in ice have been measured between -5 and -15 ¿C by exposing large single crystals of ice to low vapor pressures of HCl for several days. The solubility is found to be (1.0¿0.15)¿10-4 mol/l at -15 ¿C under a 5.6¿10-4 Pa HCl partial pressure. The diffusion coefficient is of the order of 10-12 cm2 s-1 at -8 ¿C, but the determination of the value is affected by small angle boundaries, where HCl motion is much faster. Extrapolation of these results suggests that HCl is not incorporated into stratospheric ice crystals. ¿ American Geophysical Union 1994