For centuries, cancer has been a threat to human lives. It has become one of the leading causes of death since many decades. The early detection of cancer can contribute much to reduce the morbidity rate of the disease. The goal of mammography is the early detection of breast cancer, usually through the detection of featured masses and/or micro calcification. In this paper, we proposed a methodology to detect tumors on digital mammograms. To proceed with the work, we focus on image pre processing. It is done using a scheme (a) mammogram enhancement and (b) mammogram segmentation. The first stage involves enhancement which can be outlined as enhancing the quality of the image to a much apprehensible and a better level. The second stage pertains to improving the global contrast of an image using image’s histogram. The final stage includes the segmentation to change the image representation into a form which is more substantive and easier to analyze. The experimentation of these methods is performed on mammograms of MIAS database. © IAEME Publication.