Transtympanic electrocochleography (TT ECoG) was conducted in 61 patients (61 ears) with the clinical diagnosis of Meniere's disease and 15 patients (21 ears) with cochlear hearing loss of other aetiologies to assess the ability of the method to separate different cochlear disorders. The click-evoked summation potential/action potential (SP/AP) ratio and the 1 and 2 kHz burst-evoked SP amplitudes were evaluated. Based on the TT ECoG results from 13 normal hearing subjects (15 ears) the upper limit of each variable was determined, above which a value was considered pathological, i.e. indicative of endolymphatic hydrops. The results showed that the sensitivity of the SP/AP ratio was 62% and specificity 95%. When evaluating the combinations of TT ECoG parameters with logistic regression, SP/AP ratio and 1 kHz burst-evoked SP amplitude were shown to increase the discriminating ability of TT ECoG significantly. Inclusion of the 1 kHz burst-evoked SP amplitudes increased sensitivity to 82%, without changing specificity. Inclusion of the 2 kHz burst had no effect on sensitivity or specificity.