Negative pressure wound therapy( NPWT) is used primarily for tissue defects. In recent years, cardiovascular surgery via full sternotomy is increasingly performed through small incisions, but the rate of cardiovascular surgery through median sternotomy remains high in elderly patients, who frequently have complicated cardiovascular diseases. Mediastinitis, among other surgical site infections( SSIs), is a serious complication after cardiovascular surgery that must be resolved. Mediastinitis has a high mortality rate once it occurs, and cost of treatment and a negative impact on a patient are substantial. In some countries, NPWT is for the prophylaxis of mediastinitis, but only for cases with a significant risk of SSI. To avoid SSI, prophylactic NPWT is administered in all cardiovascular surgeries through median sternotomy at our hospital. Of 641 consecutive median sternotomy patients from March 2011 to March 2021, 601 cases were able to observe the wound for at least 30 days following the surgery. In the 601 cases, we found a statistically significant difference in the incidence of SSI. The results suggest that prophylactic NPWT significantly reduces SSI after cardiovascular surgery through median sternotomy.