Breast cancer is a significant worldwide health problem. In the United States it is the most common non-skin malignancy in women and the second leading cause of female cancer mortality. Detection of breast cancer at an early stage increases the likelihood of successful treatment and long term survival. While screen film mammography is currently the most effective method of detecting asymptomatic breast cancer, there is considerable room for improvement in the areas of sensitivity and specificity, especially in cases of premenopausal women where increased breast density can obscure clinically relevant abnormalities. Tissue sample data suggests that malignant mammary tumors have electrical properties mimicking those of high-water content tissues such as muscle whereas the surrounding normal breast is more representative of low-water content fatty tissues, with the overall contrast between the two approaching an order of magnitude. This impressive contrast mechanism along with advances in model-based microwave imaging techniques provides a compelling rationale for near-field microwave breast imaging. The results presented here demonstrate that high contrast, tumor-like objects can be detected in ex-vivo breast tissue utilizing our fixed array, liquid-based microwave imaging system.