Cochlear potential response to tones was recorded with glass micropipets in all three scalae of the basal region of the cochlea of 32 anesthetized cats. The fundamental component of the potential (referred to an electrode on the chin) is represented by complex amplitudesEV, EM, ET, where the subscripts denote the scala in which the potential was recorded.EM/EVis relatively independent of stimulus level and frequency and has a magnitude of approximately 1.0–1.8 and an angle of approximately zero.EM/ETis dependent on stimulus level and frequency. Its magnitude is as large as 10 at frequencies below 300 Hz and decreases for higher frequencies. The angle of the ratio increases from approximately zero at 100 Hz to a value between +90° and +180° above 1000 Hz. Similar results were obtained from two cochleas with a severed auditory nerve, which implies that these results apply to the cochlear microphonic (CM) potential response to tones. An electric‐network model of the spatial distribution of CM is analyzed.