We investigated whether a mindfulness meditation program delivered via a smartphone application could improve psychological well-being, reduce job strain, and reduce ambulatory blood pressure during the workday. Participants were 238 healthy employees from two large United Kingdom companies that were randomized to a mindfulness meditation practice app or a wait-list control condition. The app offered 45 prerecorded 10- to 20-min guided audio meditations. Participants were asked to complete one meditation per day. Psychosocial measures and blood pressure throughout one working day were measured at baseline and eight weeks later; a follow-up survey was also emailed to participants 16 weeks after the intervention start.