501 small (SGA), 330 average (AGA) and 460 large for gestational age (LGA) babies were measured at birth. Head-chest, head-crown-rump length, and chest-crown-rump length ratios were used to evaluate the changing patterns of proportionality with increasing gestational age. The SGA group showed strong negative correlations for head-chest and head-length ratios, and positive correlations for chest-length ratios. The patterns were similar in the AGA group, only less evident. For all three measures of proportionality, correlations with gestational age in the LGA group were close to zero. In each group boys had higher head-chest ratios than girls.