Previous studies have demonstrated strong developmental trends of white matter using in vivo neuroimaging. However, few studies have examined white matter using diffusion tensor imaging across the lifespan. In the present study we examined fractional anisotropy and volume in the corpus callosum in four groups (children, adolescents, young adults, and elderly). Results revealed a curvilinear relationship in the analysis of the fractional anisotropy values for these four groups, with fractional anisotropy values increasing in childhood and adolescence, reaching their peak in young adulthood, followed by a non-significant decline in the elderly. Volumetric analysis of corpus callosum regions revealed a similar pattern, with an increase in volume from childhood and adolescence through young adulthood, and a non-significant decrease in volume in the elderly group. These results define the microstructural development of the white matter across the lifespan. Future studies are required to examine the neurobehavioral correlates of these neuroimaging indices.