Abstract: Objective To study gene expression profiling in human type I and II endometrial carcinoma. Methods Six Affymetrix human genome genechips were utilized to investigate the differences in gene expression profiles between type I and II endometrial carcinoma with bioinformatic analysis. Results Many genes were highly expressed in estrogen-dependent endometrial carcinoma, and some of them were involved in the metabolism and conversion of estrogen, while some others in estrogen regulation. CYP2C9, for instance, was involved in the conversion of estrogen sulfate to 16-hydroxy sulfate metabolite, DDC in estrogen-dependent pathogenesis of endometrial carcinoma possibly by DDC interaction with AR to enhance steroid receptor transcription. Conclusion High expression of these genes in estrogen-dependent endometrial carcinoma may provide insights into their roles in the pathogenesis and prognosis of this malignancy.