Background and purpose: Sleep-disordered breathing (SOB) is more prevalent in stroke patients than age- and sex-matched controls, but the relationship between SDB and functional outcome of stroke patients is unclear. The aim of our study was to determine the prevalence of SDB in ischemic stroke and its influence on functional outcome at 3 and 6 months after stroke onset. Methods: In a prospective study, 60 patients were selected by polysomnography (PSG). The apnea-hypopnea index (AHI) was determined 6.5 +/- 3.2 days after stroke onset. Neurologic severity at admission was assessed by the Scandinavian Stroke Scale (SSS) and Outcome by the Barthel Index (BI). Patients were evaluated on admission, 3 and 6 months after stroke onset. Results: Among the 60 patients, 39 (65%) patients had SDB (AHI >= 5); of these, 30 patients (50%) had AHI >= 15 and 18 (30%) > 30. On Logistic regression analysis, the BI at 3 months was independently predicted by SSS (OR = 0.74, 95% CI [0.62-0.88], P = 0.001) and AHI (OR = 1.09, 95% CI [1.02-1.17], P < 0.05). At 6 months, the BI was predicted only by SSS (OR = 0.83, 95% CI [0.74-0.92], P = 0.001). Conclusions: SDB is common in patients during acute phase after stroke onset. SOB appears to be associated with a worse functional outcome during the early recovery period following stroke, increasing the likelihood of dependency. (C) 2008 Elsevier B.V. All rights reserved.