Determinations of lung volumes (residual volume, functional residual capacity, vital capacity, and total lung capacity) in 82 "hospital normal" and volunteer children are reported. These values correlated best with the individual's height, but almost as well with weight and surface area. Values for lung compliance and flow resistance obtained from 77 children are also presented. Lung compliance correlated most closely with functional residual capacity and vital capacity. Resistance had a negative correlation with the height of the individual. End-expiratory intrapleural pressures as measured with an intra-esophageal balloon were found to average -6.3 cm of water for 41 of the children. Where data were available, relationships of lung volume, compliance and resistance were compared on the basis of height for infants, children and young adults, and found in most instances to be similar for all three groups.