Median sternotomy wounds are formed following most cardiac surgery. These wounds may heal with problematic scars. We hypothesise that midline sternotomy scars will scar poorly in general and in comparison with control scarring from other sites.We evaluated 50 patients with mature median sternotomy scars using the Patient and Observer Scar Assessment Scale (POSAS), the Manchester Scar Scale (MSS) and photographs. Different scar features were assessed using these scales.Patients were on average 65.9 years old, predominantly male (72%) and Caucasian (94%). Overall, 11 patients (22%) expressed concern over a symptomatic or poor scar with seven patients (14%) complaining of pruritis and three patients (6%) disappointed with the cosmesis of the scar. The clinician found five patients (10%) to have poor scarring defined as hypertrophic scarring. The predominant scarring characteristics assessed by the clinician were colouration, variable relief and increased contour which are the main areas of concern.Our study shows that median sternotomy scarring can be problematic with 1 in 5 patients symptomatic and 1 in 10 patients developing hypertrophic scarring. Thus, this predominantly Caucasion population has a low but significant rate of scar problems in comparison to median sternotomy scarring in other populations. We could not identify patient factors which were predictive for poor scarring but anatomical location may be a key factor. Overall, we believe that median sternotomy patients should be offered preventative treatment to ensure the best scar outcome.