Introduction: Malignant MCA infarction results in significant space occupying effect and intracranial pressure (ICP) increment. Due to the high mortality rate in such patients, the term malignant MCA infarction was coined. Methods: We studied a patient who developed a sudden onset of slurred speech, right hemiplegia, and decreased level of arousal. Two days later CT scan showed a massive cerebral infarct, involving the left MCA territory. Results: A transcranial Doppler exam showed a normal flow pattern in the right hemisphere, but in the left hemisphere systolic spikes without diastolic flow were observed in internal carotid artery, anterior cerebral artery, as well as in the MCA. Conclusions: The pathophysiologic mechanisms leading to BD might asymmetrically begin in cerebral hemispheres in malignant MCA infarcts.