Objective:To observe the mRNA expression of BCSG1（breast carcinoma specific gene,BCSG1）, BTF（Bcl-2-associated transcription factor，BTF）, Bcl-2（B cell lymphoma/leukemia-2，Bcl-2） and two subtypes of estrogen receptors in osteosarcoma and their implication. Methods: The expression of BCSG1, ERα, BTF, ERβ, and Bcl-2 mRNA were examined in 16 poorly differentiated osteosarcoma samples and a cell line hFOB 1.19 by quantitative RT-PCR. The relationship between their expression was analyzed. Results: The mRNA expression of BCSG1, Bcl-2 and two subtypes of estrogen receptors in the osteosarcoma tissues was significantly higher than that in the osteoblast cell line of hFOB 1.19; the expression of BTF was not significantly different. ERα/ERβ in the osteosarcoma tissues was significantly higher than that in the hFOB 1.19 cells (P<0.01). BCSG1, ERα, ERβ, Bcl-2 and BTF expression was not associated with the tumor size or patients gender. Correlation analysis showed there was a linear relationship between expression of BCSG1 and ERα，ERβ and Bcl-2, and ERα/ERβ ratio and Bcl-2. Conclusion: BCSG1 may enhance the activation of estrogen receptor-α gene transcription, and ERβ may influence the expression of Bcl-2 in osteosarcoma.