The recent evolution of tandem mass spectrometry allows to diagnose more than twenty inherited metabolic diseases within a single blood spot. Nowadays, it is technically possible to screen newborns for most of fatty acid oxidation, organic acid and amino acid disorders. An important number of prospective pilot studies, using tandem mass spectrometry, have been done worldwide. However, several technical, economical, medical and ethical problems are raised by these applications. This review is intended to focus on this technology and to resume results from the main international studies.