<p>Surgical site infections (SSIs) remain among the most common complications following elective colorectal surgery, contributing to prolonged hospitalization, higher costs, and delayed adjuvant therapy. The effectiveness of mechanical bowel preparation (MBP) with or without oral antibiotics remains controversial, with limited data from Asian populations. This study evaluated whether combining oral antibiotics with MBP (MOBP) reduces SSIs and postoperative morbidity compared to MBP alone. This was a prospective, parallel-arm, superiority randomized controlled trial conducted at a tertiary hospital in South India between June 2019 and March 2021. Patients (<i>n</i> = 140) scheduled for elective colorectal surgery were randomized to receive MBP alone (<i>n</i> = 70) or MOBP (<i>n</i> = 70). The primary endpoint was SSI within 30 days. Secondary endpoints included anastomotic leak, postoperative morbidity (Clavien-Dindo classification), readmission, length of stay, and requirement for therapeutic antibiotics. The overall SSI incidence was 20.7%, with significantly higher rates in the MBP group (31.4%) compared with the MOBP group (10.0%, <i>p</i> = 0.003). Anastomotic leak occurred in 7.1% of MBP patients versus none in the MOBP group (<i>p</i> &lt; 0.05). Readmission within 30 days was significantly reduced with MOBP (1.4% vs. 15.7%, <i>p</i> = 0.004). The mean hospital stay was shorter in the MOBP group (6.3 ± 1.1 vs. 9.9 ± 3.4 days, <i>p</i> &lt; 0.001). Postoperative morbidity was lower with MOBP, with no grade III/IV complications observed. MOBP was associated with significantly reduced SSI, anastomotic leak, readmission, and postoperative morbidity. These findings suggest a potential benefit of MOBP in elective colorectal surgery, warranting confirmation in larger multicenter trials.</p>