Background: Breast cancer has become the leading cancer in women in both economically developed and developing countries, accounting for 25% of all cancers diagnosed worldwide in 2012. The cornerstone of breast cancer control remains early detection in order to improve outcomes and survival. Thus far the only breast cancer screening method that has proved to be effective is mammography. Although mammography is the mainstay of early detection, a fundamental limitation is its low inherent contrast difference between the soft tissue structures in the breast. Mammographic specificity relies on the ability to distinguish benign from malignant breast lesions based on their margins and morphological features. When breast malignancy presents with subtle mammographic features such as focal asymmetry, its specificity is reduced. Overall, the larger portion of false -negative mammograms comprises of cancers which are visible in retrospect as ‘minimal sign’ cancers. Additional imaging with ultrasound is useful to further characterize areas of mammographic focal asymmetry, and sonographic findings are used to determine the need for subsequent biopsy for histological confirmation. However, mammographic focal asymmetry has historically not been subjected to adequate follow up, and there is limited data in radiology literature regarding ultrasound findings in its evaluation. Objective: To determine the prevalence of suspicious ultrasound findings in patients with mammographic focal asymmetry. Methods: This was a cross-sectional study, whereby women presenting for mammograms at the Radiology Department with a mammographic descriptor of focal asymmetry (as per the American College of Radiology guidelines) and recommendation for additional imaging evaluation with breast ultrasound were consecutively recruited. The whole breast ultrasound images were evaluated for normal and abnormal findings, and allotted a final imaging assessment categorisation using the ACR Breast Imaging – Reporting and Data System (BI-RADS®) ultrasound lexicon. Ultrasound BI-RADS® 1-3 categories were assigned as benign findings, while ultrasound BI-RADS® 4 and 5 were assigned as suspicious findings. A total of 141 patients were enrolled. Analysis: Data collected were entered into a spreadsheet application (Excel for Microsoft Windows, Microsoft Corporation) and analysed using Stata® version 11.2. The proportion of suspicious ultrasound findings in mammographic focal asymmetries was calculated. Results: A total of 141 patients met the eligibility criteria during the study period and were enrolled into the study. The median age was 50 years, with a range of 31 to 79 years. The prevalence of suspicious ultrasound findings in patients with mammographic focal asymmetry was 7.1%. There was equal involvement of right and