Background. There is limited information on the effectiveness of meal replacements (MRs) as a weight-loss strategy in an unsupervised community setting. Aim. To evaluate the use of MR compared with a diet book for 6 months. Subjects and Methods. Obese subjects (n = 120) with type 2 diabetes mellitus were recruited from the community in Adelaide, South Australia, and randomised to intervention or control. Subjects in the intervention were advised to consume 2 MR/day for 3 months and 1 MR/day for 3 months and follow the manufacturers' instructions from printed material and the website. Subjects in the control arm were given a commercially available diet book. Results. Consumption of 2 MR for 3 months and 1 MR for the subsequent 3 months led to weight loss of 5.5 kg (5%) and a 0.26% decrease in HbA1c while the diet book group had a weight loss of 3 kg (3%) (P = 0.027 for difference between groups) and a decrease in HbA1c of 0.15% (between group ns) in those who completed the 6-month study. On intention-to-treat (last observation carried forward) weight loss at 6 months was 3.4 kg in MR and 1.8 kg in control (P = 0.07). Decreases in HbA1c were 0.22% and 0.12%, respectively (P = ns). HDL cholesterol increased by 4% in MR and decreased by 1% in control (P = 0.004). Blood pressure decreased equally in both groups. There were reductions in fasting glucose in both groups at 6 months with no changes in LDL-cholesterol or triglyceride concentrations. Conclusion. MR confers benefits in HbA1C reduction and weight loss at 6 months in those who completed the study.