Gentamicin-specific immunolabeling was examined in the regenerating chick basilar papilla following gentamicin treatment. Surviving hair cells were labeled in the infracuticular area, predominantly in the basal body region. Label intensity in short hair cells (SHCs) was greater than tall hair cells (THCs). Quantitative examination of stereociliary bundle orientation in regenerated hair cells revealed a considerable degree of variability from normal. The orientation of SHC stereocilia was more varied than that of THC. The results suggest an association between the accumulation of gentamicin in the region of the basal body and the degree of disorientation of the cell surface. It is possible that gentamicin accumulation around the basal body compromises the ability of the centrosome to orient hair cells correctly.