The distribution of spontaneous discharge rates for auditory‐nerve fibers recorded from the guinea pig modiolus suggests that there is a greater number of fibers in the 10–30 discharges/sec range than in the cat. Some tentative groupings on the basis of discharge rates has been possible from an inspection of the cumulative frequency distribution. Three groups are suggested, with means of 10, 24, and 71 discharges/sec. The standard deviations are 2.8, 2.3 and 2.7 discharges/sec, respectively. The spontaneous discharges are reduced by COCB stimulation. The “high‐rate” group shows less reduction by COCB than the two “low‐rate” groups. For nerve fibers with best frequencies above 1 kHz, the effect of the COCB on spontaneous discharges varies as Δuvaries with frequency. Below 1 kHz, there is more COCB effect on spontaneous discharges than would be expected from Δu.