The purpose of this study was to determine the extent to which faith-based preschools promote spiritual development in preschoolers. The participants in the study were faith-based early childhood teachers and administrators from seven states. Early childhood professionals representing 11 Christian faith traditions completed written surveys or online surveys. A total of 201 faith-based educators completed the survey; 20 respondents participated in semi-structured interviews. The concurrent triangulation mixed-method design provided data on 8 program dimensions which support children's spiritual development: prayer, Bible literacy, worship, building character, service opportunities, assessment, parental involvement and context. I analyzed quantitative data using descriptive and inferential statistics. All items were examined using mean, standard deviation, frequency, and percentages. Qualitative data gathered from semi-structured interviews were coded and analyzed using NVivo8® qualitative analysis software (QSR International, Inc., Cambridge, MA, http://www.qsrinternational.com). From this data I identified the extent to which faith-based preschool programs support children's spiritual development through the practices of prayer, Bible literacy, worship, building character, service opportunities, assessment, parental involvement and context. Data analyses revealed statistically significant differences in faith-based teachers' hours of training in children's spiritual development across all program practice dimensions. A key finding of the study was that training in children's spiritual development is important regardless of the education level of the early childhood professional. Qualitative data indicated no standardized spiritual development training in faith-based preschools represented in this study. The mixed-method analysis revealed that the 8 program practice dimensions were not always connected in a framework that supported children's spiritual development. Recommendations for professional practice include a program framework to support children's spiritual development in faith-based preschool programs; training for faith-based early childhood professionals in children's spiritual development; and formulating a definition of children's spiritual development.