Neonatal screening (NS) is a medical act in the context of preventive medicine aimed at the early identification of infants affected by certain conditions that threaten their life and long-term health, for which a timely intervention can lead to a significant reduction of morbidity, mortality and associated disabilities. It emerged three decades ago in the context of prevention of mental retardation. Since then, around 600 inborn metabolic disorders have been described and technological progress has been impressive; nevertheless only around 5% of the disorders have been the object of NS. The most frequently cited reasons for the limitation are low prevalence and the lack of treatment. The tandem mass spectrometry has come in place in recent years across the globe, expanding NS to include several disorders of intermediary metabolism. This has shown, in addition to a prevalence much higher than previously thought, the benefits of early detection. The present work is a review of NS, not only from the point of view of technological/medical achievements, but also considering other factors which will affect specific disease selection, according to the social and organizational infrastructure that may expand the borders of NS.