Background: research show that cognitive behavioral therapy (CBT) is effective inreducing bulimia nervosa (BN) and binge eating disorder's (BED) symptoms. Today, with the development of technology there are efforts being made for developinga treatment to these eating disorders threw the media, most of these attempts are based on the CBT method. The size of the effect that CBT given threw the internet has on BN and BED is still not entirely clear. Research presented today are mostly based on treatments that were given threw email or Skypeor an automatic self- help stage program. These researches show heterogenic results about the effect it had on eating disorders. In this research we aim to investigate the effect size that a CBT treatment threw a smartphone application that combines a clinician online reply and an automatic feedback in addition to astandard ones a week clinic treatment has on BN and BED symptoms frequency.