Objective: Binge-eating disorder (BED) is characterized by recurrent episodes of binge eating, accompanied by a lack of control and feelings of shame. Online intervention is a promising, accessible treatment approach for BED. In the current study, we compared completers with noncompleters in a 10-session guided internet-based treatment program (iBED) based on cognitive behavioral therapy. Methods: Adults (N = 75) with mild to moderate BED participated in iBED with weekly written support from psychologists. Participants were compared on the Eating Disorder Examination Questionnaire (EDE-Q), diagnostic criteria for BED (BED-Q), major depression inventory (MDI), quality of life (EQ-5D-5L), body mass index (BMI) and sociodemographic variables. Results: Minor differences were observed between completers and noncompleters on depression. No differences were found in BED-symptoms, BMI, and sociodemographic variables. Participants who completed treatment showed large reductions in eating disorder pathology. Discussion: More research is needed to determine risk factors for attrition or treatment outcome in internet-based interventions for BED. It is suggested that iBED is an efficient intervention for BED. However, more studies of internet-interventions are needed.