BACKGROUND: Adoption of a personal health record (PHR) depends on its usability and perceived usefulness. Therefore, we aimed to assess the usability and perceived usefulness of an online PHR used for medication reconciliation and to assess the association between patient-, clinical-, hospital-, and ICT-related factors and the usability and perceived usefulness at both the in- and outpatient clinics. METHODS: A multicenter cross-sectional study was conducted with patients with either an outpatient visit (rheumatology ward) or planned admission in the hospital (cardiology, neurology, internal medicine or pulmonary wards). All patients received an invitation to update their medication list in the PHR 2 weeks prior to their appointment. One month after the hospital visit, PHR-users were asked to rate usability (using the System Usability Scale (SUS)) and perceived usefulness on a 5-point Likert scale. The usability and perceived usefulness were classified according to the adjective rating scale of Bangor et al. The usability was furthermore dichotomized in the categories: low (SUS between 0 and 51) and good (SUS 51-100) usability. Associations between patient-, clinical-, hospital-, and ICT-related factors and the usability and perceived usefulness were analysed. RESULTS: 255 of the 743 invited PHR-users completed the questionnaire. 78% inpatients and 83% outpatients indicated that usability of the PHR was good. There were no significant association between patient-, clinical-, hospital-, and ICT-related factors and the usability of the PHR. The majority of the patients (57% inpatients and 67% outpatients) classified perceived usefulness of the PHR as good, excellent, or best imaginable. Outpatients who also used the PHR for other drug related purposes reported a higher perceived usefulness (adjusted odds ratio 20.0; 95% confidence interval 2.36-170). Besides that, there was no significant association between patient-, clinical-, hospital-, and ICT-related factors and the perceived usefulness of the PHR. CONCLUSIONS: The majority of the patients indicated that the PHR for medication reconciliation was useful and easy to use, but there is still room for improvement. To improve the intervention, further research should explore patients' barriers and facilitators of using a PHR for medication reconciliation.