Surgical-site infection (SSI) is a common complication in orthopedic surgery; however, SSI after surgically managed distal femur fractures was not well studied. The aim of this study was to investigate the incidence of SSI and identify some modifiable and nonmodifiable risk factors.The patients' electronic medical records (EMRs) were reviewed to identify those who sustained a distal femur fracture and treated by open reduction and internal fixation (ORIF) between March 2014 and February 2018. SSI was defined based on the Centers for Disease Control criteria and confirmed according to the descriptions in EMR. Univariate and multivariate logistic regression models were used to determine the independent risk factors associated with SSI.Totally, EMRs of 665 patients who underwent ORIF of distal femur fractures were reviewed and 24 SSIs were found, indicating the overall incidence of SSI was 3.6%. The rate of deep SSI was 1.2% and superficial SSI was 2.4%. Staphylococcus aureus was the most common causative pathogen, either alone (7/15, 46.7%) or as a mixed infection (3/15, 20%), followed by mixed bacterial (4/15, 26.7%) and S epidermidis (2/15, 13.3%) and others. Patients with SSI had approximately twice the length of hospital stay as those without SSIs (29.0 vs 16.0 days, P < .001). Open fracture, temporary use of external fixation, obesity, smoking, diabetes mellitus, and preoperative reduced albumin level were identified as independent risk factors associated with SSI, and current smoking and preoperative reduced albumin level were the true modifiable factors.Patients should be encouraged to cease smoking as early as possible and increase the good-quality protein intake to reduce or prevent the occurrence of SSI. An explanation of the nonmodifiable risk factors should be included when patients are counseled about their increased risk of SSI.