First-order afferent single-unit responses were obtained to sinusoidal one- and two-frequency stimulation of the touch corpuscle in the cat. With two-frequency stimulation, the amount of “masking” varied with the frequency and with the amplitude of the stimuli. In some instances, the addition of a second frequency decreased unit's rate of firing below the rate at which it was responding to a single frequency. The “masked” thresholds in the two-frequency stimulation were predictable from the single-frequency rate-intensity functions for the unit, as were some of the decreased firing rates occurring during two-frequency stimulation.