Light absorption in tissue is very limited in the near-infrared range; thus brain tissue may be transilluminated effectively using standard technology. Measurements of brain oxygenation and circulation can be obtained at the cotside. Although the techniques are still under development and the application in newborn infants is still limited, the use of near-infrared spectrophotometry (NIRS) is likely to expand and hence a brief discussion of the methodology, as well as of the early results is relevant here.