Biodegradation of phenol with mixed consortia of bacterial was studied in an anaerobic batch reactor. The culture was acclimatized for a period of two months to grow in mineral salt medium contained phenol as the sole carbon source. Minimum and maximum concentrations of 50 and 1000 mg/l of phenol in the medium were used for the purpose of culture adaptation. The goals of these experiments were to determine the kinetics of biodegradation by determination of biomass growth rates and phenol concentrations with respect to incubation time. Substrate inhibition kinetics and specific growth rate were defined while data were fitted in Haldane model. The specific growth rate, half-saturation and inhibition coefficients for Haldane model were 0.067 h , 25.32 and 200 mg/l, respectively. The biokinetic parameters were used to predict the biodegradation 1 profile, which was quite consistent with the obtained experimental data. The results were useful for the estimation of relations between growth rate and substrate utilization, which may be used to evaluate mass balance for a wastewater treatment plant contained phenol compound.