Rats tested 25 days after training in a complex maze showed significant forgetting. Stimulation of the mesencephalic reticular formation immediately prior to retention testing facilitated performance in that stimulated rats made fewer errors (but did not run faster) than non-stimulated controls. Rats exposed to a contextual cue as a reminder before testing ran faster and made fewer errors than controls. Results are discussed in terms of forgetting being due to retrieval failure, and the reticular stimulation facilitating retrieval of information concerning the spatial configuration of the maze.