The electrocochleographic response is defined as the averaged electric signal recorded between the bony promontory of the cochlea and the earlobe, in response to repetitive acoustic stimuli (clicks and filtered clicks) of alternately reversing phases. Thus, the only averaged responses are the eighth‐nerve action potential and the cochlear potentials which do not reverse when the phase of the stimulus is reversed (as with the summating potential). The cochlear‐microphonic potential as well as other microphonics of different origin are canceled out. By now, more than 200 tests have been performed, covering a wide range of pathological conditions, both in adults and in children. Thus, different patterns have been observed. Four types of response can be clearly differentiated: the normal response, the recruiting response, the broad or prolonged response (vertigo, tinnitus, resonance), and the abnormal response (complex brainpathology), together with a few other types. The patterns of the normal response at each level of stimulation and during masking with white noise, as well as the different pathological patterns, are discussed with respect to the structure of the peripheral receptor, the mode of production of the whole‐nerve action potential, the cochlear and brainpathology, and the psychophysiological audiometric findings.