RESUMEN
We studied the ABO haemolytic disease of the newborn in our neonatal unit to consider their serological aspects and clinical importance. 21% of all pregnancies were ABO incompatibles. The direct antiglobulin test was positive in 46 (11.3%) of them. The Elution was positive in all the newborns with direct antiglobulin test positive (Cd+). The anti-A o anti-B antibodies concentration in mothers was higher than 1/128 in 38 (84%). The C3d complement fraction was activated in two newborns. The infants Cd+ were born to group O mothers in all cases, and nobody was premature. Twelve (26%) of Cd+ presented jaundice which need phototherapy, and one moreover exchange transfusion. The direct antiglobulin test is very useful for detect the liable newborns of serious jaundice; therefore, we thing that is suitable to make this test in infants born to group O mothers. The newborns Cd+ did not have significant anemia at first three months of life.