Procedures have been developed for obtaining urinary steroid profiles for newborn human infants. The GLC profiles contain five steroids which have been identified previously, and numerous steroids which are not yet identified. The method chosen for general use was the separation of the TMSi ethers of steroids obtained by enzymic hydrolysis, or by the Fotherby-Roy method, using a 12 ft 1% SE-30 or OV-1 column. Qualitative and quantitative comparisons can be made for normal infants, for the same infant with increasing age, and for infants with profiles altered by placental transfer of drugs. © 1969.