ObjectivesTo assess the feasibility and acceptability of a mindfulness-based stress reduction (MBSR)-based intervention and determine if the intervention is associated with a significant signal on empathy and emotional competencies.DesignTwo pre–post proof-of-concept studies.SettingParticipants were recruited at the University of Montreal’s Psychology Department (Study 1) and the CHU Sainte-Justine Department of Hematology-Oncology (Study 2).ParticipantsStudy 1: 12 students completed the 8-week programme (mean age 24, range 18–34). Study 2: 25 professionals completed the 8-week programme (mean age 48, range 27–63).InterventionStandard MBSR programme including 8-week mindfulness programme consisting of 8 consecutive weekly 2-hour sessions and a full-day silent retreat.Outcomes measuresMindfulness as measured by the Mindful Attention Awareness Scale; empathy as measured by the Interpersonal Reactivity Index (IRI)’s Perspective Taking and Empathic Concern subscales; identification of one’s own emotions and those of others as measured by the Profile of Emotional Competence (PEC)’s Identify my Emotions and Identify Others’ Emotions subscales; emotional acceptance as measured by the Acceptance and Action Questionnaire-II (AAQ-II) and the Emotion Regulation Scale (ERQ)’s Expressive Suppression subscale; and recognition of emotions in others as measured by the Geneva Emotion Recognition Test (GERT).ResultsIn both studies, retention rates (80%–81%) were acceptable. Participants who completed the programme improved on all measures except the PEC’s Identify Others’ Emotions and the IRI’s Empathic Concern (Cohen’s d median=0.92, range 45–1.72). In Study 2, favourable effects associated with the programme were maintained over 3 months on the PEC’s Identify my Emotions, the AAQ-II, the ERQ’s Expressive Suppression and the GERT.ConclusionsThe programme was feasible and acceptable. It was associated with a significant signal on the following outcomes: perspective taking, the identification of one’s own emotions and emotional acceptance, thus, justifying moving towards efficacy trials using these outcomes.