Background and purpose: Stroke is frequently associated with autonomic dysfunction, which causes secondary cardiovascular complications. This study tested whether stroke, especially with severity, assessed by National Institutes of Health Stroke Scale (NIHSS) scores or large-sized lesion correlates with autonomic dysfunction and thus predicts risk of autonomic complications. Methods: In 162 ischemic stroke patients, the authors assessed symptoms and parameters of autonomic cardiovascular modulation within acute phase after stroke onset and compared data with those of 50 healthy controls. the authors correlated clinical and subclinical symptoms with parameters of heart rate variability (HRV). Results: All time domain parameters of HRV in patients were lower than normal ones (p0,001). Frequency spectrum parameters of HRV in patients were higher than normal group (p0,05). Ln SDNN parameter in patients with NIHSS score or = 7 was lower than those with NIHSS score 7 (p0,05). Time domain parameters of HRV correlate significantly with Glasgow score. Ln SDNN parameter correlated positively with Glasgow score: r