OBJECTIVE To investigate whether different vestibular function tests such as cervical vestibular evoked myogenic potential (cVEMP) and caloric test were correlated with severity, pattern and prognosis in idiopathic sudden sensorineural hearing loss (ISSNHL). METHODS Ninety-two patients with unilateral ISSNHL were subjected to complete audiovestibular evaluation. cVEMP and caloric test results were compared with patients' initial and final audiogram. We classified patients in 4 groups as cochlear nerve (C) type, cochlear and superior vestibular nerve (C+S) type, cochlear and inferior vestibular nerve (C+I) type and cochlear, superior vestibular nerve, inferior vestibular nerve (C+S+I) type, for evaluation of the results. cVEMP and caloric tests were compared among the groups. RESULTS Abnormal caloric test results and abnormal cVEMP results were found in 50% and 31.6% patients, respectively. Multivariate analysis showed that abnormal caloric result (canal paresis) is a significant negative prognostic factor. CONCLUSIONS Initial vestibular function test can be valuable in predicting the final outcome in patients with ISSNHL.