목적: The purpose of this study is to reveal whether a group of idiopathic subjective tinnitus (IST) patients have abnormal changes in auditory P300 and to compare the results with normal subjects. 방법:Auditory P300 was performed to thirty two patients with idiopathic subjective tinnitus and they were compared to normal. The elicited auditory P300 event-related potentials were analyzed in terms of peak amplitude and latency of the P300 waveforms. Basic audiological assessments that include pure tone audiometry and immittancemetry were done to the whole study group. 결과:The results of this study showed that while P300 peak amplitudes were overall reduced for IST, it varies individually and the P300 peak latencies were statistically non significant when compared to the normal subjects. 결론:The auditory P300 waveform amplitudes were reduced in IST than normal subjects, although statistically non-significant. Possible mechanisms include that the processing of selective attention and its response to auditory tone burst stimuli associated with IST differ than that of the normal which needs further study.