Most fetal hematologic parameters show a significant relationship with gestational age: a linear increase is evident throughout gestation for several hematologic parameters. A few reports have described reference values for umbilical cord blood reticulocyte counts performed with automated hematology analyzers. Our aim was to use automated hematology analyzers (ADVIA 120; Siemens Healthcare Diagnostics) to establish reference intervals for reticulocyte parameters in cord blood from healthy newborns of 34 to 42 weeks of gestation. We also investigated whether differences in reticulocyte parameters exist between the sexes and between different weeks of gestation. We enrolled 98 healthy, appropriate for gestational age newborns. In term infants, the reticulocyte percentage, the absolute reticulocyte count, and the reticulocyte hemoglobin content decreased significantly as the gestational age increased, but the maturation subpopulations did not change significantly. We found no significant differences between the sexes. In conclusion, our results contribute to the establishment of reference intervals for cord blood from full-term newborns that are measured with an automated hematology analyzer.