Background/Aims: Circular RNAs (circRNAs) serve as potential diagnostic biomarkers. In this study, we aimed to identify a potential biomarker from peripheral blood mononuclear cells (PBMCs) of patients with postmenopausal osteoporosis (PMOP). Methods: CircRNA expression in PBMCs from three pairs of samples from PMOP patients and controls was initially detected by circRNA microarray. The changes in selected circRNAs in PBMCs from 28 PMOP patients and 21 age- and sex-matched controls were confirmed using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Next, samples from 30 PMOP patients and 20 controls were used for further verification. Pearson correlation test was performed to assess the correlation between circRNAs and clinical variables. The area under the receiver operator characteristic (ROC) curve was calculated to evaluate the diagnostic value. Results: Six differentially expressed circRNAs were identified by chip microarray analysis, of which only hsa_circ_0001275 showed consistency and statistical significance in qRT-PCR. The correlation analysis between age, body weight, height, WBC, lymphocyte and monocyte count, bone density, T-score, β-CROSSL, OSTEOC, and TP1NP showed that hsa_circ_0001275 was negatively correlated with T-score. ROC curves showed that hsa_circ_0001275 has significant diagnostic value in PMOP (AUC=0.759, P< 0.001). Conclusion: This study suggests that hsa_circ_0001275 may serve as a potential diagnostic biomarker for PMOP.