In order to estimate the frequency of G6PD deficiency in the icteric population of the Monterrey metropolitan área (MMA), in the state of Nuevo León, there were studied 829 newborn males were studied. It was found that 13 subjects were deficient of this enzyme, that is equivalent to a frequency of 1.57% and when this frequency was compared with the one that was found an a previous study in a random sample of newborn males (0.66%) no statistical difference was observed, but it was estimated that the icteric newborn males have a relative risk of 2.34 times higher than the population in general to be a G6PD deficient, and this fact suggests the necessity to establish this screening test as a routine for all icteric newborn males, in order to have an opportune detection and an appropriate counselling.