OBJECTIVES: To determine whether prolonged length of stay (pLOS) in ischemic stroke is related to delays in discharge disposition arrangement. METHODS: We designed a retrospective study to compare patients with acute ischemic stroke who experienced pLOS to those who did not experience pLOS. Patients who have had acute ischemic stroke between July 2008 and December 2010 were included unless they arrived >48 hours after time last seen normal, had an unknown last seen normal, or experienced an in-hospital stroke. pLOS was defined in our prospective stroke registry (before the generation of this research question) as hospitalization extended for ≥ 24 hours more than necessary to determine neurologic stability and next level of care/disposition for a given patient. We characterized the frequency of each cause of pLOS and further investigated the destinations that were more frequently associated with pLOS among patients with delay resulting from arranging discharge disposition. RESULTS: Of the 274 patients included, 106 (31.9%) had pLOS. Reasons for pLOS were discharge disposition (48.1%), non-neurologic medical complications (36.8%), delays in imaging studies (20.8%), awaiting procedure (10.4%), and neurologic complications (9.4%). Among patients with pLOS caused by delayed disposition, more than half were awaiting placement in an inpatient rehabilitation facility. CONCLUSIONS: For the majority of our patients, pLOS was caused by acquired medical complications and delayed disposition, most commonly inpatient rehabilitation. Further efforts are needed to prevent complications and further investigation is necessary to identify the factors that may contribute to delayed discharge to inpatient rehabilitation facilities, which may include delayed planning or heightened scrutiny of insurance companies regarding their beneficiaries.