The purpose of this study was to review existing behavioural interventions for preventing and treating obesity in adult population that were published between 2000 and September 2006. A total of 23 interventions were found. Most of these interventions targeted both physical activity and nutrition behaviours. Majority of the interventions were not based on any explicit behavioural theory. In terms of duration, the interventions ranged from 3 weeks to 9 years. Approximately half of the interventions were less than 6 months in duration. Most of the interventions were implemented by the researchers themselves. However, some interventions were implemented by nurse educators, nutritionists, trained public health nurses, dietitians, healthcare providers, fitness workers and certified diabetic educators. Most of the interventions used group sessions as the predominant method to deliver the programme. Three of the interventions used media. Majority of the interventions were implemented in patient care settings with some in community settings. The most common determinant for measuring impact of the interventions has been body mass index. Fifteen interventions showed positive change in adiposity indices while six showed no change in adiposity indices. Recommendations for enhancing the effectiveness of behavioural interventions for prevention of obesity are presented.