BACKGROUND: This randomised controlled study evaluated a computer-generated future self-image as a personalised, visual motivational tool for weight loss in adults. METHODS: One hundred and forty-five people (age 18-79 years) with a Body Mass Index (BMI) of at least 25 kg/m2 were randomised to receive a hard copy future self-image at recruitment (early image) or after 8 weeks (delayed image). Participants received general healthy lifestyle information at recruitment and were weighed at 4-weekly intervals for 24 weeks. The image was created using an iPad app called 'Future Me'. A second randomisation at 16 weeks allocated either an additional future self-image or no additional image. RESULTS: Seventy-four participants were allocated to receive their image at commencement, and 71 to the delayed-image group. Regarding to weight loss, the delayed-image group did consistently better in all analyses. Twenty-four recruits were deemed non-starters, comprising 15 (21%) in the delayed-image group and 9 (12%) in the early-image group (χ2(1) = 2.1, p = 0.15). At 24 weeks there was a significant change in weight overall (p < 0.0001), and a difference in rate of change between groups (delayed-image group: -0.60 kg, early-image group: -0.42 kg, p = 0.01). Men lost weight faster than women. The group into which participants were allocated at week 16 (second image or not) appeared not to influence the outcome (p = 0.31). Analysis of all completers and withdrawals showed a strong trend over time (p < 0.0001), and a difference in rate of change between groups (delayed-image: -0.50 kg, early-image: -0.27 kg, p = 0.0008). CONCLUSION: One in five participants in the delayed-image group completing the 24-week intervention achieved a clinically significant weight loss, having received only future self-images and general lifestyle advice. Timing the provision of future self-images appears to be significant, and promising for future research to clarify their efficacy. TRIAL REGISTRATION: Australian Clinical Trials Registry, identifier: ACTRN12613000883718 . Registered on 8 August 2013.