The National Program for the Prevention of Allergic Diseases, including the determination of IgE concentrations in umbilical cord serum at birth began in 1986. Research was conducted to determine normal umbilical cord serum values in Cuban children since no previous research had been performed. The values consulted corresponded to children from other countries with different characteristics from ours. A total of 900 neonates were examined, excluding those whose mothers had been affected by factors that increase serum IgE concentrations. IgE values higher than 10 IU/ml were also regarded as abnormal. The microELISA-IgE technique, a heterogenous immunoenzymatic sandwich type assay, was used. As reference values, a 0.64 mean, 0.06 lower limit and a 6.83 upper limit were obtained.