Eighty-six patients with head injuries with an admission Glasgow Coma Scale score between 3 and 12 were studied sequentially by transcranial and cervical Doppler sonography. On a subset of 26 patients, sequential autoregulation and CO2 reactivity testing was also performed. Patient characteristics and hemodynamic data were correlated and analyzed with respect to the final outcome. The internal carotid artery (ICA) and middle cerebral artery flow velocities followed a typical pattern. Both were depressed during the first 3 days after the trauma and then increased to a maximum between Days 5 and 7. The increase of the middle cerebral artery flow velocities was more pronounced than the increase of the ICA flow velocities, thus indicating some degree of vasospasm. The amount of subarachnoid hemorrhage on the initial computed tomography correlated with the average middle cerebral artery/ICA flow velocity ratio (r = 0.5). Subarachnoid hemorrhages on computed tomography and, to a lesser degree, subdural and intracerebral hematomas were correlated with an unfavorable outcome. Vasospasm remained subcritical, and no negative relationship to outcome could be identified. Hyperperfusion, as based on ICA flow velocities, and vasospasm were correlated with diminished vasoreactivity. However, disturbed vasoreactivities, particularly during the first days, were common and did not necessarily predict an unfavorable outcome.