A method is proposed to measure the transverse mixing coefficient using an acoustic Doppler current profiler (ADCP). Comparisons between measurements from an ADCP and an acoustic Doppler velocimeter (ADV) for mean velocity, Reynolds stress and turbulent kinetic energy (TKE) are used to determine the ability of which ADCPs can measure turbulence quantities. Profiles collected show the effects of beam geometry in measuring velocities. ADCP data for mean velocity and Reynolds stress are used in the proposed method for estimating transverse mixing. Empirical formulas for calculating the transverse mixing coefficient are computed using data collected from both the ADCP and ADV. The empirical estimates are compared between instruments and with the proposed method. Estimates from the proposed method show the most agreement with the estimate of Fischer et al. (1979), which is believed to be the most accurate empirical estimate for the laboratory flume.