Introduction Breast cancer is the most common tumor malignancy among women worldwide. Studies have revealed new class of RNA molecules named Long non-coding RNAs that play important role in tumor development, progression and metastasis. Therefore, this study aimed to evaluate long non-coding RNA lncUSMycN expression in breast cancer. Methods In this study, 40 breast tumor with invasive ductal carcinoma and 40 normal marginal tissues were collected and after RNA extraction using TRizol kit, cDNA was synthesized. Expression level of lncUSMycN was obtained by applying qRT-PCR method. In order to evaluate association of lncUSMycN expression in tumor compared to normal tissues REST software was used. Biomarker potential of lncUSMycN was evaluated by drawing ROC curve using SigmaPlot. In addition, relationship between lncUSMycN expression and clinicopathological features was analysed. Results Results from REST indicated significant upregulation of lncUSMycN in tumor tissues compared to normal marginal specimens (95% CI, p =0. 001). ROC curve analysis demonstrated the biomarker potential of lncUSMycN (ROCAUC =0. 72, p=0. 0006). Evaluation of the relationship between lncUSMycN expression and clinicopathological features revealed that there are significant association between lncUSMycN expression and early stages (95% CI, P=0. 005) and well-differentiated tumors (95% CI, P=0. 046). Conclusion Considering upregulation of lncUSMycN expression in invasive ductal carcinoma this lncRNA may be probably considered as a new potential diagnostic biomarker for breast cancer.