The catalytic, vapor-phase fluorination of dichloromethane to chlorofluoromethane with 38% hydrofluoric acid was investigated as a model system for possible direct utilization of hydrofluoric acid in the production of fluorocarbons and chlorofluorocarbons. Catalysts consisting of Cr or Ni supported on alumina and Ni, Cr, Ag, Co, La, Sn, Hg(I), Hg(II), Cu, Fe, Ru, Zn, Na, or Ca supported on activated charcoal were utilized at various reaction temperatures and reactor residence times. Alumina-supported catalysts were found to have low activities for fluorination in comparison to catalysts utilizing anhydrous HF reported in the patent literature. The low activities were attributed to low catalyst surface areas resulting from the fluorination of the catalyst with aqueous HF. Carbon-supported catalysts were found, in general, to promote thermal cracking of the CH2Cl2 feed as well as the fluorination reaction. This thermal cracking was usually sufficiently severe to result in drastically lowered yields of the desired product and low catalyst lifetime due to coking. The greatest selectivities for the desired product, CH2ClF, relative to the difluorinated product, CH2F2, at reasonably high conversions, were obtained with Sn, Cu, or Co fluorides on an activated charcoal support, although overall yields were relatively low due to thermal cracking.