Introduction & Background: Breast cancer is the most commonly diagnosed malignancy and a leading cause of cancer mortality among women after lung cancer. Diagnosis of breast tumors smaller than 1cm cans in-crease 12-year survival to 95%. Clinical Breast Ex-lamination (CBE) and Imaging (Son mammography) are the most common diagnostic methods for breast masses, though there are some controversies about their sensitivity and specificity. Because of the de crease in the age of breast cancer among the Iranian women, diagnosis of this cancer at an early stage is very important. We designed this study to compare the sensitivity and specificity of CBE and Imaging. Patients & Methods: In a Descriptive analytic study, two groups of 74 women who had referred for breast imaging were selected based on a non-randomized simple sampling method. The first group had positive CBE (breast mass) and the second had no breast mass in CBE. In all cases imaging was done. Then we cal-collated the sensitivity, specificity, PPV (Positive Pre-fictive Value) and NPV (Negative Predictive Value) of imaging, and the accuracy of CBE and imaging in both groups with the use of FNA and a one to three year follow-up as our gold standard. Results: Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CBE in mass detection were 69%, 78%, 82%, 63%, & 73% respectively; while they were 97%, 81%, 84%, 95%, & 88% for imaging, respectively. Conclusion: Based on higher sensitivity, specificity, PPV, NPV, and accuracy of imaging than CBE in de-section of breast masses in this study and other stud-is, we suggest the use of imaging with CBE in screening for breast cancer.