Breast cancer is one of the major causes of death among women all over the world. An improvement of early detection and diagnosis techniques is very important for women's quality of life. Computer-Aided Detection (CAD) systems have been used for aiding radiologists in their decision in order to solve the limitations of human observers. In this context, a methodology for mass detection on digital mammograms is presented. The proposed system was tested on several mammographic images extracted from Digital Database for Screening Mammography (DDSM) and the Mammographic Image Analysis Society (MIAS) database. Our results showed that the proposed methodology provided more accuracy than other compared techniques. The proposed system can be helpful to the radiologist by serving as a second reader in mammography screening, as it indicates that the use of the proposed methodology in the detection of masses is promising, since it achieves good rates of accuracy.