ObjectivesAngiotensin converting enzyme inhibitors (ACEI) have been shown to decrease AGV in Marfan syndrome (MFS). We sought to compare the effect of β-blockers and ACEI on aortic growth velocity (AGV) in MFS.Study designWe reviewed retrospectively all data from all patients with MFS seen at Arkansas Children’s Hospital between January 1, 1976 and January 1, 2013. Generalized least squares were used to evaluate AGV over time as a function of age, medication group, and the interaction between the two. A mixed model was used to compare AGV between medication groups as a function of age, medication group (none, β-blocker, ACEI), and the interaction between the two.ResultsA total of 67 patients with confirmed MFS were identified (34/67, 51% female). Mean age at first encounter was 13 ± 10 years, with mean follow-up of 7.6 ± 5.8 years. There were 839 patient encounters with a median of 10 (range 2–42) encounters per patient. AGV was nearly normal in the β-blocker group, and was less than either the ACEI or untreated groups. The AGV was higher than normal in ACEI and untreated groups (p<0.001 for both).Conclusionsβ-blocker therapy results in near-normalization of AGV in MFS. ACEI did not decrease AGV in a clinically significant manner.