Purpose: Surgical site infection (SSI) is a significant complication of non-reconstructive and reconstructive breast. This study aimed to assess SSI after breast surgery over 5 years in a single center in Poland. The microorganisms responsible for SSI and their antibiotic susceptibility were determined. Materials/methods: Data of 2129 patients acquired over 5 years postoperatively by the [center] were analyzed. Results: SSI was diagnosed in 132 patients (6.2%) and was an early infection in most cases (65.2%). The incidence of SSI was highest in patients who underwent subcutaneous amputation with simultaneous reconstruction using an artificial prosthesis (14.6%) and breast reconstruction via the TRAM flap method (14.3%). Gram-positive bacteria were responsible for SSI in most cases (72.1%), and these were mainly Staphylococcus strains (53.6%). These strains were 100% susceptible to all beta-lactam antibiotics (except penicillin), but were less susceptible to macrolides and lincosamides. Conclusions: SSI is a serious problem, and attention should be focused on its prevention. Reconstruction using an artificial prosthesis or via the TRAM flap method is connected to increased SSI incidence. Further studies are required to prevent SSI following breast surgery.