Complete middle cerebral artery (MCA) stroke is a life-threatening condition, which can lead to death in the form of "malignant MCA syndrome"; characterized by massive brain edema and cerebral herniation. Moreover, patients with complete MCA infarct have high mortality due to complications. The aim of this study was to evaluate the clinical predictors of in-hospital mortality in patients with complete MCA stroke. Consecutive patients with complete MCA stroke were enrolled in a prospective single center in-hospital outcome study having mortality as its end point. Among 780 ischemic stroke patients, 125 had complete MCA strokes (16%) and 44 (35.2%) of these died in hospital. A high NIHSS-score (OR 1.17 95%CI 1.03-1.34, P=0.013) and high diastolic blood pressure on admission (OR 1.05 95%CI 1.01-1.09) resulted being independent predictors of in-hospital mortality in patients with complete MCA stroke. The median value of diastolic blood pressure at admission was 90 mmHg in patients who died and 80 mmHg in survivors (P=0.01). The risk of death increased by 5% for each mmHg increase in diastolic blood pressure on admission after adjusting for other risk factors. The rate of mortality was 22% in patients with diastolic blood pressure lower than 90 mmHg, 56% for those with diastolic blood pressure between 90 and 109 mmHg and 67% for those with diastolic blood pressure higher than 110 mmHg. This study suggests that high diastolic blood pressure on admission in acute MCA stroke patients is linearly correlated with in-hospital mortality.