The advent of magnetic resonance imaging (MRI) has revolutionized the clinical approach to the evaluation of brain white matter disorders and has contributed significantly to expansion of the concept of these diseases. MRI is very sensitive at detecting white matter lesions, but conventional T1 and T2-weighted images do not provide specific pathological information about the lesions, and correlation between MRI lesion load and clinical disability is often weak. Proton magnetic resonance spectroscopy can provide chemical-pathological information of a given tissue in vivo. The use of this MR technique in brain white matter disorders has shown to improve diagnostic classification and to provide surrogate measures useful for monitoring disease evolution and response to therapeutic intervention.