Analysis of the latency, amplitude, and rise characteristics of the stapedius reflex as demonstrated on a strip recorder revealed abnormalities in patients with vestibular neuronitis and other vertigo syndromes. The findings in vestibular neuronitis, acute labyrinthitis, perilymphatic fistulas, Meniere's disease, cerebrovascular insufficiency, and metabolic vertigo are described. Alterations in the stapedius reflex included increase in latency, decrease in amplitude, stepping of the rise, and absence of the reflex. This study suggests that absence of the reflex can be associated with vertigo as well as with acoustic neuromas and other retrocochlear lesions. The findings of abnormalities in vestibular neuronitis support a brain-stem localization as the site of lesion in this disease.