Rationale Abdominal aortic aneurysm (AAA) is a prevalent condition among elderly men and may require surgical repair. Recent technical advances offer new opportunities to provide patients and next of kin with tailored and individualised information. eHealth tools have proven useful in other patient cohorts, but there are currently no validated educational eHealth tools for patients with AAA. Aim Our aim was to develop and evaluate an eHealth tool for patients with abdominal aortic aneurysm using a participatory design process. Method Patients, healthcare professionals and a technical team were involved in the development of the eHealth tool. The tool was assessed for content and usability through questionnaires, validated instruments and focus group interviews. Readability was assessed using Flesch Reading Ease Score (FRE) and Flesch-Kincaid Grade Level (FKGL). Interview data were analysed using thematic content analysis. Results Factual content and illustrations were accurate and in line with current information routine. Readability assessments produced a mean FRE score of 42.2 (+/- 3,7) and mean FKGL of 10 (+/- 1), implying that the eHealth tool may be difficult to comprehend for certain users. However, participants in the focus group interviews found the tool to be understandable, relevant and easy to use. Conclusion The developed eHealth tool is acceptable, understandable and usable for the potential end-users. Further evaluation of the usability of the tool and effect on outcome in clinical care is warranted. This is the first educational eHealth tool for patients with AAA and has potential to contribute to improved communication and quality of care for AAA patients.