Clinical outcome of internal carotid artery (ICA) occlusion is highly variable and the reason is uncertain. To study the predictive factors of clinical outcome and stroke recurrence in patients with ischemic stroke associated with unilateral atherosclerosis-related ICA occlusion. Prospective study in neurology department of a single hospital. We prospectively studied 66 patients who suffered from first-ever ischemic stroke associated with unilateral atherosclerosis-related ICA occlusion over a period of two years. The end point was death or stroke recurrence. Chi-square or Fisher's exact test was used to analyze predictors of early functional outcome. Multivariate analysis was used to analyze predictors of death or stroke recurrence within two years. Higher age (>or=70 years) predicted a worse functional outcome (P=0.049). Total anterior circulation syndrome (TACS) was associated with a poor functional outcome (P<0.001), but lacunar syndrome had a better outcome (P=0.001). Stroke in evolution predicted a poor outcome (P=0.001), while those with symptom improvement had a better outcome (P=0.016). Pneumonia predicted a poor outcome (P=0.021). Five patients expired and 22 patients suffered from recurrent stroke in the following 24 months. Previous transient ischemic attack (TIA) and anemia were associated with a higher risk of death or recurrent stroke within two years (P=0.036, P=0.012). High age, TACS, stroke in evolution and pneumonia were predictors for poor functional outcome. Previous TIA and anemia were predictors for death and recurrent stroke within two years.