BACKGROUND: Relapsing MS (RMS) is a lifelong disease without a cure, usually diagnosed between 20-40 years of age. Being newly diagnosed with RMS is a highly stressful event due to the unpredictable disease course after diagnosis. Thus, it is imperative that persons with MS have the skills and support to cope with the negative physical and emotional effects of the disease. The objective of this study was to assess whether a mindfulness-based intervention (MBI) would improve coping skills and thus lessen the negative consequences of stress due to being newly diagnosed with RMS. METHODS: This was a single-blind (assessor), randomized, prospective study of a 10-week MBI vs. usual standard of care in persons newly diagnosed (within 1 year) with RMS, recruited from one tertiary care MS clinic in London (ON), Canada. The MBI was administered in group format with a trained MBI facilitator. Primary outcomes included the Brief COPE measure and the Hospital Anxiety and Depression Scale (HADS) subscales. Secondary outcomes included measures of perceived stress, cognitive function, fatigue, and quality of life. Exploratory (tertiary) outcomes included serum markers of inflammation and stress. Subjects were assessed at baseline, post intervention (or equivalent) and 6 months later. A repeated measures multivariate analysis of covariance (MANCOVA) was used, with baseline scores employed as covariates and the test scores, to compare longitudinal changes, immediately after the MBI sessions and 6 months later. RESULTS: Twenty-five subjects were recruited (16 MBI, 9 controls) for two (Fall and Spring) MBI interventions over 1.5 years. All controls completed the study, while 4 MBI participants did not, leaving 21 subjects in the analysis. Most were women (17, 81%), with a mean age of 37.1 ± 9.4 years. Two thirds had already started a DMT at the time of consent; the median EDSS was 2.0 (0.0-4.0). The groups were well matched on baseline characteristics, with the exception of months since diagnosis (MBI 6.4 ± 6.5 vs. control 3.6 ± 2.8, p=0.023). All controls completed the study, while 4 MBI participants did not. The MBI group improved significantly on the COPE measure when compared to the control group (p=0.024) pre and post intervention; the MBI group also improved significantly on the HADS depression subscale (p=0.007). There was no significant difference over time on the HADS anxiety subscale (p=0.179). The effect size on COPE was 0.56 and 0.40 on HADS-D. On the secondary outcomes, there was a significant improvement on the Perceived Stress Scale (p=0.015). The exploratory outcomes were not significantly different. None of the outcomes were significant at the six-month follow-up. CONCLUSION: This pilot study demonstrates that an MBI may improve coping, depression and perceived stress in newly diagnosed (within one year) persons with RMS in the short term. Future research to confirm these results, as well as further investigate measures to extend the benefit beyond the immediate intervention.