Objective To observe the effects of tamoxifen and anatrazole endocrine therapies for breast cancer on bone metabolism.Methods A total of 150 patients with breast cancer who received endocrine therapy after radiotherapy were divided into anatrazole (ANA) group (n=75) and tamoxifen (TAM) group (n=75).All patients were treated for 12 months.The serum levels of calcitonin (CT), osteocalcin (BGP), and bone alkaline phosphatase (NBAP) were measured before and after treatment.The bone mineral density of L₂-L₄ was measured by X-ray absorptiometry.Results After treatment, the CT and NBAP of the two groups were higher than those before treatment, while the BGP and L₂-L₄ bone mineral density were lower (all P<0.01 or P<0.05).After treatment, the levels of CT, BGP, and NBAP in the ANA group were higher than those in the TAM group, while the L₂-L₄ bone mineral density was lower (P<0.01).Conclusion Both the endocrine therapies using TAM and ANA have significant effects on the levels of bone metabolism, especially ANA.