Breast cancer (BC), the most common women malignancy, comes second for cancer-related deaths. Roles of long non-coding RNA H19 (lncH19) re-expression and rs217727 SNP in BC is still obscure. We aimed at evaluating lncH19 expression, determining rs217727 distribution and assessing its impact on gene expression among BC females and its possible utilization as a marker for BC diagnosis or prognosis. This study performed on 200 females; 100 BC females, 50 benign breast lesion (BBL) females and 50 healthy controls. LncH19 polymorphism (rs217727) was genotyped with restriction fragment-length polymorphism. Relative quantitation of lncH19 expression done by real-time PCR. LncH19 rs217727 distribution showed significant increases in frequencies of homozygous TT variant genotype of co-dominant model, CT+TT dominant model and T allele in BC versus controls. There was significantly increased T allele frequency in BC versus BBL. LncH19 expression significantly increased in BC versus BBL and HC. LncH19 upregulated in BC with metastasis which suggests its prognostic value. ROC curve analysis showed the possibility of the lncH19 for being a BC diagnostic biomarker. The diagnostic performance for expression showed 85% sensitivity and 83% specificity. LncH19 rs217727 T allele carries excess BC risk. LncH19 expression might be a diagnostic and prognostic marker for BC.