Background: Breast-conserving surgery (BCS) has gained wide acceptance as the treatment of choice for early-stage breast cancer. One of the primary goals of BCS is to obtain tumor-free resection margins. In practice, the excision of a palpable breast carcinoma is guided by preoperative diagnostic images and the intraoperative tactile skills of the surgeon. The somewhat ‘blind’ approach of using palpation-guided surgery is known to be highly inaccurate, with studies worldwide reporting positive resection margins in up to 41% of patients. In recent years, ultrasonography has emerged as an effective guidance tool during surgery and ultrasound-guided surgery has been introduced into breast cancer surgery as a method of excising nonpalpable breast cancer. Objective: The aim of this study is comparing ultrasound-guided vs palpation-guided conservative breast surgery in obtaining tumor-free resection margins. Methods: This study was a prospective randomized controlled clinical trial where patients with early breast cancer (T1-T2) and eligible for breast conserving surgery are randomly assigned (1:1) into two arms. Arm A: included the patients who will undergo ultrasound-guided breast conserving surgery. Arm B: included the patients who will undergo the conventional palpation-guided breast conserving surgery. Results: Overall, 142 patients undergoing breast conserving surgery were enrolled: 71 were allocated to the Ultrasound-guided (US) group (Arm A) and 71 to the Palpation-guided (PG) group (Arm B). Patient and tumor characteristics were comparable between the two groups. Age, Body mass index, tumor laterality, tumor location and tumor stage were comparable in both groups and statistically insignificant. Despite that the final tumor size was comparable between both groups, IOUS significantly reduced the main specimen volume and the least negative margin width (p<0.001). The median operative time was significantly longer in the US group bey around 27 min than in the PG group and this was statistically significant in favor of the PG surgery (p<0.001). The involved resection margin rate was significantly higher in the PG group and thus the need for reoperation (p<0.001). Conclusion: IOUS is the only method allowing a true real-time visualization and continuous control of resection margins during all phases of BCS. In our single-institution study, IOUS demonstrated clear superiority over palpation-guided surgery in both oncological and surgical outcomes except for the operative time (smaller excision volume yet, with optimum resection margins). IOUs provides much better tumor localization in small breasts with dense fibroadenosis. Since all the other available localization techniques (including palpation) limit the surgeon’s visual guidance during BCS, IOUS could be regarded as one of the most significant modern technological innovations in the field of breast cancer surgery, restoring sight to the breast surgeon. Our findings strongly suggests that the integration of IOUS in breast conserving surgery could be regarded as a highly beneficial surgical approach.