Removal of certain organic pollutants from the environment may be difficult due to their poor water solubility and high vapour pressure. Particularly, these are factors limiting the use of biological remediation methods because they affect the bioavailability of xenobiotics. Therefore, an important issue in the biofiltration of gasses is the removal of hydrophobic compounds. This paper presents the results of research showing relation the application of a chosen surfactant (betaine) to the efficiency of toluene biofiltration. The research was conducted on a laboratory-scale biofilter. Elimination capacity and removal efficiency at different biofilter loads have been researched. The maximum elimination capacity was 21.2 and 32.3 g/m3h for the control bed and for the bed to which the betaine solution was applied, respectively. For the results of the experiment, statistical analyses and model calculations were performed. The results were compared with the reference literature.