Breast cancer is the second most common cause of cancer-related mortality among women. The aim of the present study is to investigate the diagnostic accuracy of ultrasonography in correlation with histopathology in suspected patients of breast mass. In this cross-sectional study, ultrasonography and histopathology was done on 50 clinically suspected patients of breast mass in the Department of Radiology and Imaging Mymensingh Medical College Hospital, Mymensingh from 1st April 2008 to 30th March 2009 for the period of one year. Women of all ages were included in the study. Findings of USG and histopathology were correlated. In diagnosis of malignant mass by USG, 32(64%) of cases were diagnosed as malignant and 18(36%) cases as other than malignant. Here 31(86.1%) of sonographically diagnosed malignant lesions were also proved as malignant lesion by histopathologically and 1(7.1%) other than malignant. Out of 18 sonographically diagnosed cases of other than malignant lesions 13(92.9%) were proved histopathologically and 5(13.9%) did not match with sonographic findings as other than normal. USG, in diagnosis of malignant lesion, sensitivity was 86.1%, specificity 92.9%, positive predictive value (PPV) (96.6%), negative predictive value 72.2% and accuracy was 88.0% and comparable to other study. In the conclusion this study permits to conclude that ultrasonography has significant sensitivity, specificity, accuracy, positive predictive value and negative predictive value in the diagnosis of both benign and malignant breast mass.