Background: The round block technique (RBT) is an oncoplastic technique used in the excision of peri-areolar breast lesions especially in small to medium-sized breasts with moderate ptosis. Objective: Our study aims to introduce the technique of modified round block technique (MRBT) and to compare RBT and MRBT in peripherally located tumors as regards the oncological safety and cosmetic outcomes. Patients and methods: From October 2018 to October 2021, a randomized controlled clinical trial was conducted on 40 female patients with early stages of breast cancer. Patients selected had tumors at least 2 cm away from the nipple-areola complex (NAC) and an expected excision volume not exceeding 20% of the breast volume. Patients' demographic data and tumor characteristics were recorded and analyzed. Results: The MRBT group has a significantly shorter operative time (P-value 0.016). Positive margin involvement was recorded in 2 cases requiring re-excision in the RBT group. Six patients developed seroma formation which was significantly higher in the MRBT group (P-value 0.048). A significantly lower mean change in areolar diameter was observed in the MRBT group (P-value 0.032). Two cases developed local recurrence, one in each group. No cases of distant metastasis were encountered during the follow-up. MRBT group has a significantly higher cosmetic outcome than RBT (P-value 0.03). Conclusion: The MRBT is an oncoplastic technique suitable for the excision of breast tumors in different breast quadrants especially peripherally located tumors in patients with small to medium-sized breasts and when the excision volume is not exceeding 20% of the breast volume.