A biofilter model was developed to predict the performance a biofilter treating benzene. Model parameter values were obtained from literature sources and both steady state and dynamic conditions were examined. The results indicate that the biofilter is most sensitive to interstitial velocity, biofilter height, specific surface area and first order biodegradation rate constant. Using the developed default set of model parameter values, dynamic biofilter performance was evaluated using a pulse input to the biofilter. If a benzene regulatory limit of 0.08 g/m\sp3 was imposed on the biofilter system, the biofilter modelled in this study would be able to successfully predict input pulse heights and the corresponding pulse duration. Recommendations for further study include, incorporating into the model Monod kinetics and inhibition to account for biofilters treating multiple contaminant input streams.