Single unit activity in the posteroventral cochlear nucleus (PVCN) was recorded for a variety of stimulus conditions. The units were classified according to their response characteristics. The locations of units were plotted onto a three-dimensional block model of the cochlear nucleus. Certain types of units that responded best to the onsets of stimuli were located predominantly in the octopus cell region of the PVCN. The remainder of the PVCN, which contains a rather heterogeneous collection of small and multipolar cells, was found to contain several types of units with the dominant type being "chopper" units.