AbstractBackground: The mechanism of tooth development is a complex process regulated by numerous genes including transcription factors, growth factors, and other intra‐ and extracellular molecules. Especially, transcription factors play a central role in gene expression, regulating a wide spectrum of biological processes including organogenesis. Substantial evidence has been demonstrated by a number of studies using genetically engineered animal models. However, detailed molecular mechanisms of tooth development have not been completely elucidated, partially because numerous genes that play essential roles in tooth development remain unidentified. Results: In this study, we conducted an expression‐based screening using gene expression database and in situ hybridization assays. Based on the gene expression database “EMBRYS,” 207 out of 1,520 genes were expressed in the maxillary and/or mandibular processes and thus were selected for further analysis by section in situ hybridization. Among these candidates, 28 genes were newly identified as potential factors associated with tooth development by in situ hybridization assays with frontal sections of embryonic day 13.5 and 14.5 mouse embryos. The expression patterns were also examined at embryonic day 16.5 and 18.5. Conclusions: These results will contribute to elucidating the mechanisms of tooth development and to improving the technology for regeneration of tooth. Developmental Dynamics 241:1217–1226, 2012. © 2012 Wiley Periodicals, Inc.