Background: The potential benefit of eHealth interventions in patients with abdominal aortic aneurysm (AAA) is uncertain. The primary aim of this study was to investigate the effect of an eHealth intervention on anxiety in patients with AAA undergoing surgery. Methods: A single-centre randomized clinical trial of patients with AAA scheduled for surgical repair was undertaken. The intervention group received an eHealth tool and psychosocial support besides standard care. The control group received standard care. The analysis of treatment effects was performed as intention-to-treat and per protocol analysis. The primary outcome measure was anxiety mean score (Hospital Anxiety and Depression Scale Anxiety (HADS)-A). Secondary outcomes measures were HADS Depression and short-form 12-item health survey mean scores. Results: Some 120 participants were randomized. No effect on anxiety mean scores was found in the intention-to-treat analysis (-1.21 versus -0.54, P=0.330). Among those randomized to the intervention, only 30 of 60 participants used the eHealth tool (application (app) users). The app users were younger and had a higher educational level. A decrease in anxiety mean scores was noted in those who used the app in the per protocol analysis (-2.00 versus -0.54, P=0.028). The intervention group stated a lower physical-component health-related quality of life (HRQoL) (-4.32 versus -1.16, P=0.042) but mental-component HRQoL and depressive symptoms were unchanged. Conclusions: Delivery of an eHealth intervention in this RCT did not result in an improvement in anxiety scores in patients awaiting AAA surgery. Uptake of the eHealth tool was low, although it resulted in lower anxiety scores in those participants who actually used it.