[Objective] To determine the expression of angiopoietin-2 (Ang-2) in eutopic and ectopic endometrium of endometriosis and adenomyosis, and to investigate the role of it in the pathogenesis of endometriosis and adenomyosis. [Methods] Expression of Ang-2 mRNA in the eutopic and ectopic endometrium of 65 patients with endometriosis (endometriosis group) and 40 patients with adenomyosis (adenomyosis group) and the expression of Ang-2 mRNA in the normal endometrium of 30 patients (control group) without endometriosis and adenomyosis were detected by RT-PCR. [Results] Expression levels of Ang-2 mRNA in the eutopic and ectopic endometrium with endometriosis and adenomyosis were significantly higher than that in control group, and there was not significant relevance between the expression level and the clinical staging. [Conclusion] Expression of Ang-2 mRNA has a high level in the eutopic and ectopic endometriotic tissues with endometriosis and adenomyosis. Ang-2 may play a very important role in the development of endometriosis and adenomyosis and may relate to the pathogenesis of endometriosis and adenomyosis.