BACKGROUND: Recent study has revealed that large intergenic non-coding RNA-ROR (linc-ROR) is aberrantly expressed in a number of cancers including breast cancer. However, whether circulating linc-ROR in plasma could be used for breast cancer diagnosis and dynamic monitoring is not clear. OBJECTIVE: The objective of this study is to determine if plasma linc-ROR could be applied as a biomarker for the diagnosis and dynamic monitoring of breast cancer. METHODS: We tested the expression levels of linc-ROR in 24 pairs of tissue samples and 96 plasma samples from breast cancer patients by quantitative real time-polymerase chain reaction (qRT-PCR), and analyzed the correlation between plasma linc-ROR levels and clinico-pathological characteristics. Receiver operating characteristic (ROC) curve was used to assess the diagnostic power of plasma linc-ROR, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 153 for breast cancer. Furthermore, we explored the monitoring values of plasma linc-ROR for breast cancer by analyzing the preoperative and postoperative plasma linc-ROR levels of the same patients. RESULTS: The expression levels of linc-ROR were significantly higher in breast cancer tissues and plasma than the levels in the control (P < 0.05). The linc-ROR expression levels in plasma were correlated with lymph node metastasis (P < 0.05), estrogen receptor (ER) (P < 0.05) and progesterone receptor (PR) (P < 0.05). The area under the ROC curve of plasma linc-ROR was 0.758 (sensitivity 80.0%; specificity 73.3%), which was higher than CEA and CA153 values from the same patients obtained. Combination of the linc-ROR with the conventional biomarkers might produce better diagnostic ability. Additionally, the linc-ROR expression levels of plasma in postoperative patients were lower than those in preoperative patients (P < 0.05). CONCLUSION: Overexpressed linc-ROR may be a potential biomarker for the diagnosis and dynamic monitoring of breast cancer.