Objective To evaluate the risk factors for sternal wound infections after various cardiac operations. Methods We retrospectively analyzed the clinical data of 2 924 consecutive patients (28% female) in our hospital from 2010 to 2014 year. Their median age was 69 years (interquartile range of 60 to 76 years). Procedures included isolated coronary artery bypass grafting (CABG), isolated valve repair or replacement, and valve procedures plus CABG. Results Sternal wound infection was detected in 110 (3.8%) patients among the 2 924 patients: 67 of 1 671 patients (4.0%) after CABG, 17 of 719 (2.4%) after valve operations, and 26 of 534 (4.9%) after valve+CABG operation. In the CABG patients, bilateral internal thoracic artery harvest procedure, operation time>300 minutes, diabetes, obesity, chronic obstructive pulmonary disease, and female were independent risk factors for sternal wound infection. In the valve operation patients, only revision for bleeding as an independent predictor for sternal infection. For combined valve plus CABG patients, revision for bleeding and operation time>300 minutes were independent risk factors for sternal infection. Conclusion Risk factors for sternal wound infections after cardiac operations vary with the type of surgical procedure. In patients undergoing valve operations or combined operations, procedure-related risk factors (revision for bleeding, operation time) independently predict infection. In patients undergoing CABG, not only procedure-related risk factors but also bilateral internal thoracic artery harvest and patient characteristics (diabetes, chronic obstructive pulmonary disease, obesity, female) are predictors of sternal wound infection. Preventive interventions may be justified according to the type of operation.