Three-ring polycyclic aromatic hydrocarbons (PAHs), and phenanthrene (Phe) in particular, are the main pollutants found in the waste flue gases from organic material combustion in energy generation processes. Quantitatively, the most abundant gaseous contaminant emitted in these processes is CO2. Therefore, the aim of this paper has been to study the influence of different CO2 concentrations on the phenanthrene adsorption in a postcombustion cleanup process when carbonaceous materials are used to remove low concentrations of phenanthrene from a hot exhaust gas stream. Adsorption isotherms were obtained using CO2 and phenanthrene concentrations in the ranges of 0-30% and 0.025-3.2 ppmv, respectively. The process temperature was fixed to 150 degreesC in all runs. All the obtained isotherms were properly fitted to the Freundlich adsorption model and their parameters determined by regression analyses. A negative influence Of CO2 in phenanthrene adsorption capacity was observed, probably due to a competitive effect between CO2 and phenanthrene for the adsorption sites within the carbonaceous material. However, it was found that high CO2 concentrations did not affect the phenanthrene adsorption more negatively than low CO2 concentrations. It was thus concluded that the most suitable carbonaceous materials for phenanthrene abatement in flue gases were those having a wide pore distribution with a high average micropore diameter. The development of mesoporosity in adsorbents promotes phenanthrene adsorption because it favors both the access of phenanthrene molecules into the micropores and the phenanthrene multilayer adsorption. Finally, the Yoon and Nelson mathematical model was applied to simulate the breakthrough curves. This model was able to predict the adsorption breakthrough in all the runs. Nevertheless, problems arose when trying to fit breakthrough curves at relative concentrations higher than 70% in those adsorbents with narrow micropore distributions.