We report an atypical presentation of sporadic Creutzfeldt-Jakob disease (CJD) in a 74-year-old woman that illustrates the difficulty in diagnosing this rare, but important, cause of rapidly progressive dementia. Despite well-established criteria, this diagnosis is often missed or substantially delayed (Table 1). In this case, a precipitous cognitive decline associated with a urinary tract infection initiallysuggested delirium. Although atypical CJD was considered as a cause when symptoms persisted, a definitive diagnosis was established postmortem when the cerebrospinal fluid (CSF) prion protein 14-3-3 tested positive. Creutzfeldt-Jakob disease must be considered in the differential diagnosis of rapidly progressive dementia as Connecticut accounts for approximately three of the more than 200 cases diagnosed nationally.