The clinical entity of delayed endolymphatic hydrops was first defined by Schuknecht in 1978. It constitutes the development of symptoms consistent with endolymphatic hydrops either ipsilateral or contralateral to an ear with a profound hearing loss. We report our experience with this condition amongst 394 patients with Meniére's syndrome followed prospectively. Of 24 patients with the ipsilateral condition, nearly half responded to medical treatment. Thirteen patients underwent vestibular nerve section and the outcome, as assessed by a disability grading system, was very satisfactory. The proportion of patients undergoing vestibular nerve section (54.9%) was substantially higher than patients with classical Meniére's syndrome during the same period (5.4%) reflecting the increased severity of the symptoms. The contralateral form was less frequently seen and patients were more refractory to treatment. The audiological definition of delayed endolymphatic hydrops appears somewhat arbitrary, as these patients form a continuous spectrum with other Meniére's syndrome cases, occurring in association with less marked degrees of sensorineural hearing loss.