Transcriptional regulation of the p53 gene plays an important role in expression of wild type p53 and in elevated expression of mutant p53 genes in tumor cells. In addition, alterations in p53 transcription levels occur in response to changes in the cell cycle. The following review describes current knowledge regarding the structures of both the human and murine p53 transcriptional regulatory regions and the factors that have been demonstrated to regulate promoter activity. The potential role of defects in transcriptional regulation of the p53 gene in oncogenic transformation is discussed.