Background: Evaluation of the degree of severity of injury, coma duration, and prediction of outcome are integral parts of present-day management of severe traumatic brain injury (TBI). Objective: To investigate whether evaluation and prediction of outcome in early phase after severe TBI is possible by means of single-voxel proton magnetic resonance spectroscopy ( (1) H-MRS). Materials and Methods: Proton spectra were acquired from the posterior part of normal-appearing frontal lobes having predominantly white matter in 72 patients with severe TBI within a few days of trauma, mean 9.5 days and also in 30 controls. Results: (1) H-MRS studies revealed lower ratios of N-acetylaspartate (NAA)/Choline (Cho) and NAA/ Creatine (Cr) and higher ratios of Cho/Cr in patients with TBI when compared to the control group. In patients with severe TBI, NAA/Cr, NAA/Cho and Cho/Cr ratios were significantly correlated with the initial Glasgow Coma Scale score (GCS) (P=0.004, r =0.439, P=0.018, r =0.364, P=0.004, r = -0.762, respectively), and with the clinical outcome, Glasgow Outcome Scores (GOS) (P=0.006, r =0.414; P=0.007, r =0.412; P=0.016, r = -0.775, respectively). An equation including clinical and spectroscopic variables, which can predict coma duration fairly accurately, was also obtained. Conclusions: (1) H-MRS may be a novel method of assessing brain function, estimating coma duration, and predicting outcome in patients with severe TBI.