Background: Normal ranges for WBC in healthy newborns have been challenged as too restrictive. Objective: To establish normal values for WBC in the first 24 hrs. of life. Study design: Cross sectional study. Subjects: 2830 healthy infants born to mothers with PROM (not infected/on no antibiotics), who were enrolled in a multicentre trial of induction of labour vs. conservative management. Methods: Total WBC, neutrophil (T) and immature neutrophil (I) counts and I/T ratios were determined within 24 hrs of birth. Median and the 95 and 5 percentiles were plotted against time for each test. Results/Conclusions: Based on the largest sample to date, the distribution of data, medians, and the 5 and 95 percentiles differ from previous reports, showing higher medians and wider ranges Future research: The diagnostic test characteristics of these nomograms in predicting infection will be established by using data from 114 infected infants in the study, who had blood samples drawn at < 24 hrs after birth.