There is a recognized overlap between eating disorders (EDs) and obsessive-compulsive disorder (OCD) in terms of diagnosis, phenomenology, epidemiology, and psychological characteristics related to the disorder. In light of these similarities, a cognitive inference-based therapy (IBT) program, shown to be effective in treating OCD, was adapted for EDs. This case study describes the application of IBT treatment for a 35-year-old woman diagnosed with bulimia nervosa who also demonstrated overvalued ideation related to her body weight and shape. Over a 20-week period, the client's ED pathology significantly decreased. Notably, the frequency of binge episodes was reduced by 90% from pre- to posttreatment and by 100% at 6-month follow-up. Significant reductions were also observed in dietary restriction and overvalued ideation. This case study has important implications for the treatment of individuals with both an ED and strong overvalued ideas.