In a study of working memory, the performance of rats under titrating-delayed-nonmatching- to-position (TDNMTP) procedures was examined. Overall accuracy and the number of trials completed were inversely related to titration value, whereas the highest delay attained was directly related to titration value. When given intraperitoneally, scopolamine significantly reduced the highest delay attained without significantly affecting other performance measures for most administrations. Subcutaneous administrations significantly reduced all performance measures, suggesting that, as in most prior studies, the drug's disruptive effects were not limited to memory processes. These findings demonstrate the feasibility of using TDNMTP procedures with rats, but further research is necessary to determine if such procedures are especially valuable in studying working memory and drug effects thereon. (Contains 4 figures.)