Background and Purpose: New effective recanalization therapies are currently available for acute ischemic stroke; yet a vast majority of stroke patients are left untreated. The lack of early recognition may be because often times, stroke patients present with atypical manifestations that resemble other conditions (which are referred to as “stroke chameleons”). We set to study the proportion of patients with delayed stroke recognition in a single center. Methods: We performed a retrospective analysis of a prospectively collected data over a 9-year period. All adult patients discharged with the diagnosis of ischemic stroke or transient ischemic attack (TIA) were identified and traced for their diagnosis on admission. Those cases with a diagnosis other than ischemic stroke or TIA on admission were identified as possible stroke chameleons and categorized into different groups according to the occurrence of neurological or non-neurological manifestations at presentation. Results: Of 2,303 cases with discharge diagnosis of ischemic stroke or TIA, 919 (39.9%) were found to be possible stroke chameleons. More than half of these patients (58.4%) presented with neurological manifestations including disorders of the somatic sensation (33%), alteration of consciousness (30%), and disorders of speech/language (11%). The remaining possible stroke chameleons had manifestations pertaining to other organ systems such as cardiopulmonary, gastrointestinal, systemic infection, trauma, and thromboembolic events elsewhere. Conclusions: In our cohort, a surprisingly large percentage of possible stroke chameleons was observed. It is important to confirm our findings, study the impact on clinical outcome, and develop strategies for early stroke patient recognition.