Neonatal screening for congenital adrenal hyperplasia advances the moment of the diagnosis of the illness and in consequence the beginning of the treatment, this prevents the appearance of salt-wasting crisis that could lead to the newborn death. Discrepancies exist as to which is the most appropriate protocol for the development of the screening program. The most critical aspects are: the threshold of 17-hydroxyprogesterone that should be considered as an abnormal result and the moment of sample taking. For the introduction of this screening program it is necessary to consider, not only the results of the scientific knowledge, but also the circumstances and real consequences in a certain population.