In the catalytic oxidation of carbon monoxide over silver wool the C-13 kinetic isotope effects in the 343-453 K temperature range were experimentally determined and the following temperature dependence was found: 100 ln(k(12)/k(13)) = (3.398 - 630/T) +/- 0.083. A reaction CO/O-2 gas mixture of 1:2 ratio was used in a static system with initial pressures ranging from 20 to 40 kPa. Under these conditions the reaction is of order 1 with respect to CO and order 0 with respect to O-2 and CO2 pressure. The apparent activation energy is 59.3 +/- 1.7 kJ mol(-1). In our theoretical interpretation of the experimental data various geometries of(CO2)double dagger and (CO3)double dagger transition states were applied, and only a (CO2)double dagger with an interbond angle of 110 degrees and CO stretching force constants of 1700 and 1000-1400 N m(-1), respectively, with an asymmetric reaction coordinate was found to be acceptable.