Residence time distributions (RTDs) are investigated in a multistage agitated contactor (MAC) for Newtonian fluids. A suitable computational fluid dynamics (CFD) simulation strategy is presented in this work. The effects of operating conditions, reactor geometries, and a turbulent parameter for the RTD curves are discussed. The resulting mean residence times and variances via the CFD simulation are in good agreement with the experimental data. Various liquids are used to simulate the RTD under different flow conditions. The Reynolds number with respect to the impeller speed ranged from 2600 to 50 000. The simulation results show that a cascade of stirred tanks with a back flow (CTB) model is more suitable to describe the flow behavior in a MAC with few stages than an axial dispersion model.