This study presents the results of a simulation work performed using activated sludge model no. 3 (ASM3) extended with biological phosphorus removal processes to determine the most influential kinetic parameters in the model prior to a comprehensive calibration and simulation work. Sensitivity analysis was performed for a total of 44 kinetic parameters separately and the results were compared with the base scenario in which all parameters are set to their defaults. Besides, principal component analysis was employed to extract patterns of the most influential parameters. The values of parameters were changed between 70% and 130% of their defaults and effluent concentrations as well as removal efficiencies for performance parameters were obtained to calculate normalized sensitivities of the model outputs with respect to each kinetic parameter. Results showed that, out of 44 kinetic parameters, 10 of them can be used for calibration purposes and the effects of the rest are negligible.