Objectives:The purpose of this study was to explore Motivational Interviewing (MI) applied through Co-Active Life Coaching (CALC) skills on obese adults’ (ages 35 to 55) weight, waist circumference, self-esteem, functional health status, quality of life, self-efficacy, physical activity, and nutrition.Design:A single-subject multiple-baseline method research design was utilised.Method:One volunteer Certified Professional Co-Active (CPCC) coach provided 18 35-minute weekly coaching sessions with eight women residing in London, Ontario whose BMI was ≥30. Measures included weight, waist circumference, the Rosenberg Self-Esteem Scale, Short-Form 36 (SF-36) Health Survey, the World Health Organization Quality of Life Questionnaire, self-efficacy questionnaires, The International Physical Activity Questionnaire, and two three-day dietary intakes. Participants returned six months after their final coaching session for a follow-up weigh-in and waist circumference measurement. Visual inspection was used to analyse weight and waist circumference to determine whether changes were observed. Statistical interpretations were used to analyse the remaining measures to determine whether a clinically significant change was made.Results:Visual inspection indicated a change in weight and waist circumference. Clinically significant changes were observed in participants’ self-esteem, functional health status, quality of life, self-efficacy, physical activity, and nutrition. At the six-month follow-up, three participants had gained weight (although two participants were still below their baseline weight), one participant continued to lose weight and four participants maintained the weight lost during the intervention phase.Conclusions:MI using CALC skills is a behavioural intervention that is an effective tool in aiding individuals to conquer their battle with weight.