Pulmonary autograft replacement (Ross procedure) is used as an alternative to prosthetic aortic valve replacement patients with aortic valve disease. There are limited data on incidence and risk factors for dilatation and dysfunction of the neo-aortic after the Ross procedure. Ross procedure was performed in 100 patients at our institution between 1993 and 2011. In 76 patients, complete follow-up data were available. Their median age at surgery was 16 (0.4-58) years (76 % males; 95 % with congenital aortic valve disease). Median follow-up duration was 5.2 years (0.3-16.0 years). We analyzed their clinical and echocardiographic follow-up to identify possible risk factors for neo-aortic root dilatation and dysfunction. Ross procedure included reduction plasty of the native ascending aorta in 25 % of patients. During follow-up, 21 patients (28 %) developed neo-aortic root dilatation, 38 patients (50 %) dilatation oft the native ascending aorta and 7 patients (9 %) at least moderate neo-aortic regurgitation. Univariate risk factors for neo-aortic root dilatation were preoperative aortic regurgitation (p = 0.04), concomitant reduction plasty of the ascending aorta (p = 0.009) and a longer duration of follow-up (p = 0.005). Younger age at surgery was associated with dilatation of the ascending aorta (p = 0.03). Reoperation on the neo-aortic root because of severe dilatation was necessary in 6 patients (8 %), where 2 patients had at least moderate neo-aortic root regurgitation. Neo-aortic root and aortic dilatation are common after the Ross procedure. This is often combined with neo-aortic valve dysfunction. Close follow-up of these patients is mandatory.