This study investigated if and how an individual counselling program, based on motivational interviewing, affects lifestyle changes that contribute to smoking cessation and physical activity enhancement. The participants were 2 men and 6 women aged 25 -54 years. The program consisted of 12 individual weekly counselling sessions based on motivational interviewing. There was a 9 month follow up (monthly sessions, weekly telephone calls). A semi-structured interview was used to evaluate the effectiveness of the program after the intervention. Qualitative content analysis was used, along with the In Vivo Software in organizing the data from the interview. At the end of the follow up, three participants stopped smoking, four participants turned to light smokers (<10 cigarettes per day) and only one person failed to change smoking behavior. The participants reported that the discussion and communication with the advisor were very helpful, such as the support, the commitment, the resistance and the goal setting techniques. The gains that the participants experienced were a general life-style change, smoking cessation or smoking reduction, motivation, sensitization, self-esteem, self-knowledge, safeness, stress reduction, relaxation and better physical condition. It seems that motivational interviewing greatly contributes to helping adults to quit or reduce smoking and adopt a healthier lifestyle.