Chemical dynamic method for measuring volumetric mass transfer coefficient in gas-liquid dispersions is presented which takes into account non-ideal mixing in liquid phase in terms of RTD and oxygen probe response curves monitored simultaneously in single point in the batch. The responses of oxygen and spectrophotometric (or conductivity) probes on a pulse of mixture of sodium sulfite and tracer (NaNO3 or NaCl) solutions are monitored. The method can be used both in the batch and the continuous arrangement for liquid. Experiments were performed in one-impeller and three-impeller vessels, the latter involving large effect of backmixing of liquid phase on interfacial mass transfer. Reliability of the method was tested in coalescing (distilled water) and noncoalescing (0.5 M Na2SO4 solution) batches by comparing the results from pure oxygen and air absorption, and by comparing the obtained results with those measured in the identical apparatus by the independent dynamic pressure method.