Axonal sprouting of the ipsilateral retinal projections in the adult rat was evaluated as a consequence of contralateral eye removal. In all experimental animals a generalized axonal sprouting was present at each region of normal termination represented by increased quantity and granule size of preterminal degeneration. Increased distribution occurred unequivocally only in the superior colliculus. For partial injury of a single neuron system in the adult brain, axonal sprouting is postulated as a mechanism of internal system reorganization in which system repair and possible recovery or maintenance of function can occur.