The importance of cholinergic systems for spatial working memory was examined by injecting scopolamine at varying times during a 5 hr-long retention interval imposed between the rat's fourth and fifth choices in an 8 arm maze. Regardless of whether or not the testing procedure required the rats to adopt a spatial solution for the task, scopolamine (1.0-5.0 mg/kg) did not impair retention in a manner that was suggestive of an effect on working memory. Modest deficits observed in some conditions appeared to result from drug effects on performance. Previous findings of impaired acquisition of accurate spatial behavior by scopolamine-treated rats evidently reflect an influence of the drug on physiological systems other than those necessary to maintain working memory for spatial information.