Background and aims: Effective and cost-efficient interventions are essential to reduce the impact of common mental disorders and facilitate work participation. The PROMISE project applied person-centered eHealth intervention as an add-on to the usual care to improve the health of patients with common mental disorders. Thus, the aim of this economic analysis was to evaluate the cost utility of this intervention compared to the usual care alone. Methods: An open randomized controlled trial was conducted from February 2018 to June 2020 in western Sweden with the sample size of 110 in the intervention and control groups, each. In the intervention group, individuals received person-centered eHealth services through telephone and a web-based digital platform in addition to the usual care. Meanwhile, the control group received only the usual care. Data were collected using questionnaires and by extracting from national and regional databases and registers, including follow-up records. The incremental cost-effectiveness ratio (ICER) was determined using Quality-Adjusted Life Years (QALYs) as the measure of health outcomes. This evaluation was conducted from a societal perspective, and the analysis followed the intention-to-treat principle. The study had a one-year time horizon. Results: The add-on person-centered eHealth intervention to the usual care resulted in an ICER value of -3776895, which was based on an average incremental cost of SEK -20296 and an average incremental gain in QALYs of 0.0054. This approach exhibits a 76.3% probability of being cost-effective. Conclusion: The add-on person-centered eHealth interventions to the usual care dominated the usual care alone in reducing the impact of common mental disorders, such as depression and anxiety, for patients taking sick leave Keywords: Person-centered care, Mental disorders, eHealth, Economic evaluation, Sick leave