Binge eating disorder (BED) is a common and under-treated condition with major health implications. Cognitive behavioural therapy (CBT) self-help manuals have proved to be efficient in BED treatment. Increasing evidence also support the use of new technology to improve treatment access and dissemination. This is the first randomised controlled study to evaluate the efficacy of an Internet guided self-help treatment programme, based on CBT, for adults with threshold and subthreshold BED. Seventy-four women were randomised into two groups. The first group received the six-month online programme with a six-month follow-up. The second group was placed in a six-month waiting list before participating in the six-month intervention. Guidance consisted of a regular e-mail contact with a coach during the whole intervention. Binge eating behaviour, drive for thinness, body dissatisfaction and interoceptive awareness significantly improved after the Internet self-help treatment intervention. The number of objective binge episodes, overall eating disorder symptoms score and perceived hunger also decreased. Improvements were maintained at six-month follow-up. Dropouts exhibited more shape concern and a higher drive for thinness. Overall, a transfer of CBT-based self-help techniques to the Internet was well accepted by patients, and showed positive results for eating disorders psychopathology. --------------------------------------------------------------------------------