BACKGROUND AND OBJECTIVE: By assessing unilateral utricular function at the acute unilateral vestinuloneuritis (Acute UVN), we sought to determine the ability of the subjective visual vertical (SVV) during eccentric rotation (dynamic SVV) in localizing the site of the lesion in unilateral vestibular neuritis (UVN). METHODS: The static SVV and dynamic SVV of fifteen patients diagnosed with acute UVN were enrolled within 10 days of onset (average 7 days). First, the static SVV was measured in a dark booth without rotation. The dynamic SVV was measured during rotation with an eccentric displacement of the head to 3.5 cm from the vertical rotation axis during a constant velocity of 300 degrees/s. RESULTS: In the acute stage of UVN, the static SVV showed an increase in deviation to the side of the lesion compared to those of normal subjects. Also, we found 73% of abnormal findings in Acute UVN patients by assessing static conventional SVV. The dynamic SVV had a statistically significant increase in deviation to the side of the lesion compared to those of normal subjects and 93% patients showed beyond normal range. CONCLUSIONS: The dynamic SVV would be an effective method in the diagnosis and localization of acute unilateral vestibularneuritis.