The incidence of wound infection and delayed wound healing was greater in neonates and infants less than 3 months old who had undergone open heart surgery through a median sternotomy than in older patients. To reduce these problems, we stopped using continuous absorbable braided suture for skin and subcutaneous tissue closure in August 2005, and used interrupted non-absorbable monofilament suture instead. Around the same time, we adopted hydrocolloid dressing as a substitute for gauze dressing. We evaluated the effectiveness of wound management by comparing 28 patients who had undergone surgery before August 2005 with 22 patients who underwent surgery after that date. The age at surgery was 45±30 and 21±23 days, respectively. The patients in the earlier period were significantly older than in the later period. There were no significant differences in body weight at surgery, operating time, or cardiopulmonary bypass time between the groups. The time for wound closure was 30±11 and 22±4 min, respectively, and the patients were hospitalized after surgery for 61±41 and 44±31 days. Both were significantly shorter in the later group of patients. There was a single case of mediastinitis, in the earlier period. Wound infection or delayed wound healing occurred in 8 patients in the earlier period and in 3 patients in the later period. The only 4 patients who required wound resuturing were all in the earlier period. The incidence of wound infection and delayed wound healing tended to be low in the later period. We believe that interrupted non-absorbable monofilament sutures improved the wound microcirculation and that the hydrocolloid dressing accelerated wound healing via its moisturizing and heat-retention action, pH buffering ability, and bacteriostatic activity, and that all these contributed to the better outcomes in the later period.