A small, high frequency response conductivity probe has been constructed and used at sea. Measurements were made from an instrument platform towed at 35 m depth in the seasonal thermocline at ocean station P during the 1977 Mixed Layer Experiment (MILE). The microconductivity probe consists of four parallel electrodes plated on one side of a 0.5 mm¿3 mm¿3 mm ceramic chip with the electodes aligned in the direction of flow. Comparisons with a microbead thermistor signal show that the conductivity signal was dominated by temperature up to the maximum frequency response of the thermistor, about 25 Hz. Therefore, under the conditions of the experiment, the conductivity probe signal measured temperature, but to smaller scales and higher frequencies than the microbead thermistor. Conductivity gradient spectra peaked in regions of different microstructure activity at frequencies between 11 and 96 Hz corresponding to temperature diffusive cut-off wavelengths between 16 and 1.85 cm. The estimated frequency response of the probe based on flushing of the conductivity cell volume is 700 Hz at the 1.78 m/s average towing speed during MILE. Spatial resolution of the probe appears to be adequate to resolve the smallest scale temperature gradients encountered during the experiment. Conductivity gradient spectral levels in some regions of microstructure activity were 10--1000 times larger than spectral levels of the noise.