Effects of kainic acid lesions of the striatum on reafferentation of the striatum produced by intraventricular substantia nigra (SN) grafts were investigated. Rats with unilateral 6-hydroxydopamine lesions of the SN received intrastriatal kainic acid lesions or sham lesions, and then received fetal (E16) SN or sciatic nerve grafts in the lateral ventricle. The depth of reafferentation of the striatum by catecholaminergic neurites from SN grafts was significantly increased in rats with kainic acid-induced striatal lesions, as compared to the sham-lesioned controls. No reafferentation was seen in the control animals with sciatic nerve grafts. These data suggest that striatal injury promotes the growth of dopaminergic neurites from SN grafts.