Although gadolinium-enhanced magnetic resonance imaging (Gd-MRI) has been used to indicate the presence of a subclinical labyrinthitis in patients with idiopathic sudden sensorineural hearing loss (ISSHL), its sensitivity in daily clinical practice is unknown. We describe Gd-MRI findings in 27 ISSHL patients taking part in a prospective multicenter clinical trial. MRI findings were related to the severity of the hearing loss, vestibular involvement and the time interval between the occurrence of ISSHL and imaging. Pathological enhancement of the cochlea indicating a labyrinthitis was found in one patient with ISSHL. In 26 cases, no pathological enhancement could be established. Study results indicate that the present sensitivity of Gd-MRI is low for detecting subclinical viral labyrinthitis in patients with ISSHL. To improve the sensitivity of MRI in ISSHL, we recommend that imaging is performed as early as possible, preferably before treatment is started.