Abstract: The Triple-Negative Breast Cancer (TNBC) subtype accounts for 15 percent of all breast cancers and is characterized by the lack of estrogen, progesterone, and HER2/Neu receptors. The objective of this study is to compare and contrast microRNA expression level profiles from triple-negative breast cancer versus normal breast cell lines. MicroRNA was extracted from normal (AG11132) and TNBC (HCC1806, HCC70, and MB157) cell lines and subjected to microarray analysis. Microarray analysis revealed that a number of microRNAs (miR-21, 34a, and let-7 family miRNAs) were shown to be differentially expressed in TNBC versus the normal breast cell lines. It was shown that TNBC cells have a differential microRNA expression profile when compared to normal cells. Microarray analysis revealed that microRNA expression profiles cluster the TNBC cells separately from the normal cells. The findings suggest that microRNAs could potentially be used as biomarkers to diagnose TNBC, and could potentially be used as drug-targeted therapies in the future.