The rate coefficients for the reactions of OH with five halocarbons 3CH2F (HFC 134a), CF3CHClF (HCFC 124), CF3CHCl2 (HCFC 123), CH3CHF2 (HFC 152a), and CH3CF2Cl (HCFC 142b)>, which are proposed as alternatives to chlorofluoromethanes, have been measured. A pulsed photolysis system and a discharge flow apparatus were used to measure the rate coefficients between approximately 210 and 425 K. Use of the complementary techniques enabled identification of systematic errors and minimization of these errors. The obtained values are compared with values previously measured by other groups. This data base is used in the subsequent paper to calculate the atmospheric lifetimes of the five compounds. ¿ American Geophysical Union 1991