BACKGROUND: Mindfulness has been applied in the United States and Europe to improve physical and psychological health; however, little is known about its feasibility and efficacy in a Brazilian population. Mindfulness may also be relevant in tackling obesity and eating disorders by decreasing binge eating episodes-partly responsible for weight regain for a large number of people-and increasing awareness of emotional and other triggers for overeating. The aim of the present study protocol is to evaluate and compare the feasibility and efficacy of two mindfulness-based interventions (MBIs) addressing overweight and obesity in primary care patients: a general programme called Mindfulness-Based Health Promotion and a targeted mindful eating protocol called Mindfulness-Based Eating Awareness Training. METHODS/DESIGN: A randomised controlled trial will be conducted to compare treatment as usual separately in primary care with both programmes (health promotion and mindful eating) added to treatment as usual. Two hundred forty adult women with overweight and obesity will be enrolled. The primary outcome will be an assessment of improvement in eating behaviour. Secondary outcomes will be (1) biochemical control; (2) anthropometric parameters, body composition, dietary intake and basal metabolism; and (3) levels of mindfulness, stress, depression, self-compassion and anxiety. At the end of each intervention, a focus group will be held to assess the programme's impact on the participants' lives, diet and health. A feasibility study on access to benefits from and importance of MBIs at primary care facilities will be conducted among primary care health care professionals and participants. Monthly maintenance sessions lasting at least 1 hour will be offered, according to each protocol, during the 3-month follow-up periods. DISCUSSION: This clinical trial will result in more effective mindfulness-based interventions as a complementary treatment in primary care for people with overweight and obesity. If the findings of this study confirm the effectiveness of mindfulness programmes in this population, it will be possible to improve quality of life and health while optimising public resources and reaching a greater number of people. In addition, on the basis of the evaluation of the feasibility of implementing this intervention in primary care facilities, we expect to be able to suggest the intervention for incorporation into public policy. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02893150 . Registered retrospectively on 30 March 2017.