Objective: Select pre-, peri-, and post-operative variables, predictive for sternal wound complications (SWC), in a clinical setting. Methods: We analyzed pre-, peri-, and post-operative data of 3815 patients who underwent a primary isolated bypass grafting. 100 patients (2.6%) had post-operative SWC. Unifactor and multifactor risk analysis, were used for statistical analysis. Results: Unifactor analysis identified age (P=0.05), obesity (P=0.001), lung disease (P=0.001), extracorporeal circulation >100 min (P=0.02), graft choice (P=0.01), post-operative low cardiac output, reoperation, nephrological, pulmonary problems (P<0.001) as risk factors. Multifactor analysis, identified obesity (P=0.005), reoperation (P=0.01), nephrological (P=0.0001), pulmonary problems (P=0.001) and No-IMA-use (P=0.05) as independent predictors. Age <50 years (P=0.04) decreased the risk for SWC. There is, however, an interaction of the graft-use and the pre-operative and post-operative predictors, that can mask the precise effect of the graft-use. Conclusion: Reoperation, nephrological and pulmonary problems are strong predictors, obesity and age independent preoperative risk factors for sternal wound complications.