Sternal stability is essential to prevent serious infective complications after sternotomy. This paper examines whether nitinol thermoreactive clips reduce sternal wound infection rates in obese patients [body mass index (BMI) >30] compared with sternal wires. Methods: All patients with BMI >30 undergoing cardiac surgery via median sternotomy between February 2008 and February 2013 in our institution were divided into two groups depending on sternal closure technique sternal wires or thermoreactive clips. Comparison was made using propensity-matched analysis with sternal wound infection as the primary outcome. Results: Of 1371 patients, 826 (60 ) had thermoreactive clips and 545 (40 ) sternal wires. The sternal wires group was older (mean age 66.62 ? 10.1 vs 64.35 ? 9.8 years, P = 0.00) with a greater proportion of females (39 vs 26 , P = 0.00). In unmatched group comparison, both superficial sternal wound infection (thermoreactive clips 4 vs wires 3 ) and deep infection (thermoreactive clips 3 vs wires 0.6 , P = 0.00) were more common in the thermoreactive clips group. More patients in the thermoreactive clips group required debridement and a larger number had vacuum-assisted closure [thermoreactive clips 10 patients (1 ) vs sternal wires 2 (0.4 )]. Propensity-matching yielded two groups of 356 patients. There was no difference in sternal wound infection rates [thermoreactive clips 19 patients (5 ) vs sternal wires 15 (4 ), P = 0.58] or deep sternal infection rates [thermoreactive clips 9 patients (3 ) vs sternal wires 3 (1 ), P = 0.11]. Conclusions: Thermoreactive clips did not have an advantage in the prevention of superficial or deep sternal wound infection in obese patients undergoing sternotomy.