Recent prevalence estimates of cognitive dysfunction in MS fall as high as 54-65%,21 with impairments having been documented in cognitive realms such as attention, executive control, working memory, and episodic memory. Deficits in long-term episodic memory in MS are a major complaint of patients, and have been noted to be a significant contributor to disability by numerous researchers.4,15,18 While the early studies of memory functioning in MS suggested that the memory impairment was due to difficulties in the retrieval of information from long term storage,19,26 more recent studies have challenged these conclusions. Specifically, research at KMRREC has clearly shown that verbal memory impairment in MS is primarily a function of poor acquisition of information, rather than retrieval failure.6,7,8 MS subjects require more trials to learn the same amount of information as healthy control subjects. However, once this learning has occurred, both MS and healthy control groups have comparable recall at 30-minutes, 90-minutes, and 1-week time periods (Appendix B).6,7,8 Given the apparent deficit in the acquisition of new information and the impact this deficit has on an individual's quality of life, the amelioration of this deficit is critical. The treatment of memory deficits has been the focus of research in numerous neurological populations, yet it has received little attention in MS.17 Although multiple authors have highlighted the need for cognitive rehabilitation techniques in MS,24,16 only a few existing cognitive rehabilitation programs have been aimed at improving attentional deficits,23 communication skills, 13 or memory and new learning within MS.1,2,14 In addition, few studies have examined the use of cognitive enhancing medications to treat cognitive deficits in MS. Greene and colleagues (2000) conducted a 12-week trial of Donepezil for the treatment of cognitive symptoms in MS, noting the medication to be useful for this population. Yet few other medication trials have been accomplished. Modafinil is a psychostimulant medication, FDA approved for the treatment of Narcolepsy, with potential application for the treatment of learning and memory dysfunction in MS.