The purpose of this study was to determine antibiofilm effect of combined sonication treatment with organic acid on polystyrene surface and to develop a predictive model for Escherichia coli biofilm inactivation. Polystyrene plates containing E. coli biofilm were exposed to sonication with different inactivation solutions (PBS, lactic acid and acetic acid) at different temperatures (20, 40 and 50oC) and times (2 and 5 minutes). The effects of temperature, time and inactivation solution on E. coli biofilm removal were found to be statistically significant (p