OBJECTIVES: To determine whether weight loss interventions, which combine dietary, exercise and behaviour change strategies, result in reduced weight, body mass index (BMI) and waist circumference in people with coronary heart disease (CHD), hypertension (HTN) and/or type 2 diabetes mellitus (T2DM). DESIGN: A systematic review of studies published 1997 to 2010. DATA SOURCES: The electronic databases MEDLINE, PsycINFO, COCHRANE, CINAHL and EMBASE. REVIEW METHODS: Studies were included if samples were: >/= 18 years old, overweight or obese (BMI 26-39.99 kg/m(2)), and diagnosed with CHD, T2DM and/or HTN. Only randomised controlled trials (RCTs) or systematic reviews of RCTs reporting group-based interventions that combined dietary, exercise and behavioural change strategies and outcomes for weight, BMI and/or waist circumference up to 12 months were included. Two researchers extracted data and appraised quality, with a third making final decisions. RESULTS: Eight RCTs were included (total n = 1428). Participants' mean age was 60.4 years and 61% were female. Interventions varied by contact time, content and delivery. Mean weight loss ranged from -2 kg to -4 kg (SD 4 kg) at 3-4 months, -1.3 kg to -8.2 kg (SD 4 kg) at 5-6 months and -0.87 (SD 0.57 kg) to -6.9 kg (SD 4 kg) at 12 months. Of the few studies that measured waist circumference the mean reduction was -3.1 cm at three and 12 months. CONCLUSIONS: Weight loss interventions that combine exercise, diet and behaviour change strategies result in minor weight loss at 3-12 months in people with CHD, T2DM or HTN. Further research is required to determine the most effective and efficient methods.