Canonical flexible transition state theory is applied to the recombination of CX3 radicals (X = H, F, CI) using a simple model for the potential-energy surface. The limiting high-pressure rate coefficient, k(infinity), is calculated, using Monte Carlo integration with stratified sampling for the three reactions in the temperature range from 300 to 2000 K. k(infinity) exhibits a negative temperature dependence, which becomes more pronounced as the size of X increases. There is a good agreement between the present results and some of the available experimental data. The factors that influence the negative temperature dependence of k(infinity) and the relative magnitude of k(infinity) for the three reactions are investigated.