Breast cancer remains the second leading cause of cancer death among women worldwide. It is significantly contributing to the cancer surgical load. Though various advancement in therapies, surgery remains the primary treatment, particularly modified radical mastectomy (MRM]. However, the most common postoperative complication is noticed as seroma formation which affects 3-85% of cases. This study aims to identify patient and surgery specific risk factors influencing seroma formation. The prospective observational study was conducted at Bangabandhu Sheikh Mujib Medical University (BSMMU], Dhaka, Bangladesh. Study included women aged >20 years with stage I or II breast carcinoma undergoing MRM with Level II axillary dissection. Key findings include a significant association between increased age, high BMI, diabetes mellitus, shorter drain duration, and increased postoperative drain output with seroma formation. Electrocautery dissection showed a higher seroma incidence compared to sharp dissection. The tumor characteristics did not significantly impact seroma risk. Axillary lymph node dissection (ALND] emerged as a major driver. Optimized postoperative care, including individualized drain management, is critical for reducing seroma-related complications. The study underscores the necessity for tailored postoperative strategies to improve patient outcomes and calls for further research to establish standardized seroma prevention protocols in breast cancer surgery.