This paper presents a lumped-parameter model that stimulates the in vivo electrical properties of a guinea pig cochlea implanted with a multielectrode stimulating array. A basic model of the low-frequency electroanatomy in a normally functioning guinea pig cochlea is developed by adding critical membrane capacitances to Strelioff's resistive network model [1]. The basic model of normal cochlear tissues is modified to account for anatomical and physiological differences between a normal and implanted cochlea, which results in an impedance model of an implanted cochlea. Simulating the results of in vivo cochlear stimulation verifies the accuracy with which the modified cochlear model represents electrical properties within an electrically stimulated cochlea. Generalized simulations using this model suggest a straightforward phasing scheme capable of achieving sharply focused, channel-independent multielectrode cochlear stimulation.