Abstract <p>The paper presents an experimental study on the residence time distribution (RTD) of a liquid-phase flow in a plate-type microfluidic reactor of a combined geometry, which includes a mixing zone and a meandering channel. The experiments are performed by stepwise tracer injection followed by UV detection within the volumetric flow rate range of 0.5–2.0 mL/min. Cumulative curves <i>F</i>(<i>t</i>) and differential curves <i>E</i>(<i>t</i>), characterizing the deviation of the actual flow from the ideal regime, are obtained. The average residence times are calculated, showing the expected dependence on the flow rate. Four one-parameter models are used to interpret the obtained data, specifically, axial dispersion, cascade, Y laminar, and M laminar models. The model parameters are determined by nonlinear regression analysis with minimization of the sum of squared deviations. It is found that with an increase in flow rate from 0.5 to 2.0 mL/min, the Peclet criterion increases from 37 to 125, while the Y model parameter decreases from 0.47 to 0.32, which indicates a change in the velocity profile. Based on the analysis of the model parameters, it is found that with increasing flow rate and Reynolds number, the flow approaches the ideal displacement mode. It is shown that all models satisfactorily describe the experimental curves; however, the smallest approximation errors are achieved for the axial-dispersion and cascade models, while the Y and M models, directly related to the shape of the velocity profile in the channel, demonstrate the greatest adequacy in terms of physical interpretation. The obtained results confirm the effectiveness and prospects of using a microfluidic reactor for processes requiring minimal longitudinal mixing and precise control of contact time in the fields of low-tonnage chemistry and specialized synthesis.</p>