Purpose: The purpose of this study was to offer a better understanding of the development of neuromotor control for speech breathing and provide a normative data set that can serve as a useful standard for clinical evaluation and management of young children with speech disorders involving the breathing subsystem. Method: Speech breathing was studied in 60 healthy children, including 10 boys and 10 girls, each at ages 4, 5, and 6 years. A variable inductance plethysmograph was used to obtain volume changes of the rib cage, abdomen, and lung as well as temporal features of the breathing cycle. Results: Results indicated that breathing behavior was influenced by height and age but not gender. Some speech breathing behaviors were found to be highly variable, whereas others were more systematic. Conclusions: The data from this investigation demonstrate that the refinement of the speech breathing mechanism is gradual and presumably takes place from approximately 3-10 years of age. The rate of change associated with speech breathing parallels that observed in other subsystems of speech production. (Contains 4 figures and 2 tables.)