Mammography is a medical imaging technique that combines, low-dose radiation and high-contrast, highresolution film for examination of the breast and screening for breast cancer. This paper proposes a Random Forest Decision Classifier (RFDC) for classifying mammograms. Results of screening the mammograms are organised by classification and finally grouped into three categories i.e., Normal, Cancerous and Benign. Experimental results show that this method performs well with the classification accuracy reaching nearly 90% in comparison with the already existing algorithms.