AbstractWe have measured the percent change in 2, 3‐diphosphoglycerate (DPG) concentration in cord blood erythrocytes and adult erythrocytes during incubation at 37°C using31P nuclear magnetic resonance spectroscopy. DPG concentrations remained unchanged during the first 4.0 ± 0.9 h (mean + SD) for cord blood erythrocytes and 6.0 ± 1.0 h for adult blood erythrocytes. After this plateau phase, cord blood and adult erythrocyte DPG concentrations decreased at a rate of 11.6 ± 0.4 and 11.4 ± 0.5% of the baseline DPG concentration per hour, respectively. There was no statistically significant difference in the percent rate of DPG degradation when comparing cord blood erythrocytes to adult erythrocytes during either the plateau phase or the decay phase. Starting at the onset of the decay phase, the neonate 3‐P DPG resonance shifted downfield at a rate of 0.03 ± 0.006 ppm per hour; the adult 3‐P DPG resonance shifted downfield at a rate of 0.02 ± 0.003 ppm per hour. © 1986 Academ