Importance: The aggressive growth of cholesteatoma in the middle ear involves the angiogenesis of the cholesteatomal perimatrix. However, which transcription factor is involved in this process remains unclear. Objective: To identify a transcription factor that supports the aggressive growth of cholesteatoma by controlling the angiogenesis of cholesteatoma in the middle ear milieu. Design: We used clinical specimens for the profiling of angiogenic factors and their regulatory transcription factors in cholesteatoma. Human skin keratinocytes and endothelial cells were used for evaluation of the effects of candidate transcription factor on the angiogenic factor regulation and endothelial cell proliferation. Setting: University departments of otolaryngology-head and neck surgery. Participants: Eight clinical cholesteatomal and 8 control specimens were used for cellular and molecular biologic evaluation. An additional 8 cholesteatomal and 8 aural skin specimens were used for microarray studies. Main Outcome Measures: The expression of vascular endothelial growth factor, interleukin 8, and cyclooxy-genase 2 as measured by means of immunohistochemistry and molecular biologic methods. Results: Human aural cholesteatomal specimens were rich in the expression of angiogenic factors such as vascular endothelial growth factor in the cholesteatomal matrix and perimatrix, accompanied by the transcription factor inhibitor of DNA binding (Id1). We found Id1 to be an essential regulator of vascular endothelial growth factor. In addition, potent angiogenic factors, including interleukin 8 and cyclooxygenase 2, were regulated by Id1 via different molecular mechanisms. Conclusions and Relevance: The transcription factor Id1 controls the angiogenesis of cholesteatoma through the regulation of vascular endothelial growth factor, interleukin 8, and cyclooxygenase 2, which are responsible for the angiogenesis of cholesteatoma. Id1 may serve as a good target for the treatment of cholesteatomal progression in the middle ear milieu.