Background: Seroma is the most common problem occurring after breast cancer surgery, causing patient discomfort, repeated seroma aspirations with the risk of infection, prolonged hospital stay, delayed wound healing, skin flap necrosis, delay in receiving adjuvant therapies, and higher surgical expenditures. The purpose of our study is short term follow up" within two months after operation" to evaluate the effectiveness of using Tetracycline and closure of the dead space in reducing seroma after Modified Radical Mastectomy (MRM). Patients and methods: Interventional study was conducted on 56 females with breast cancer to evaluate different techniques for reduction of seroma formation after modified radical mastectomy at general surgery department of Zagazig University Hospitals, during the period from October 2018 to April 2020. Patients were divided into 2 groups each one enrolls 28 patients Group A: we used tetracycline, suction drain and tight bandage while in Group B: we used mechanical closure of dead space, suction drain and tight bandage, "without tetracycline" All patients were subjected to Demographic data taking, complete clinical examination, Laboratory investigations and breast ultrasound. Results: In this study the percentage of seroma occurred in total cases was (26.8%) this is considered good results when compared to worldwide percentage (73%). In group A (Tetracycline) seroma occurred in 32% of 28 cases and 21.4% of 28 cases in group B. Conclusion: There was no significant difference between using Tetracycline and mechanical closure of dead space in reducing seroma after MRM.