 Introduction We developed a service to identify potential study participants through electronic medical records and deliver study invitations through patient portals.Methods The service was piloted in a cohort study that used multiple recruitment methods.Results patient portal messages were sent to 1303 individuals and the enrollment rate was 10%, n equals 127. The patient portal enrollment rate was significantly higher than email and post mail, 4%.Strategies.Conclusion patient portal messaging was an effective recruitment strategy. This article was authored by Kelly T. Gleason, Daniel E. Ford, Diana Goumas, and others.