The aim of the present study was to examine the prevalence of eating disorder symptoms in patients with obsessive-compulsive disorder (OCD). Additional aims were to assess whether having comorbid eating disorders could influence the treatment outcome for OCD, and if symptoms of eating disorders were reduced after treatment for OCD. The sample consisted of 93 patients with a primary diagnosis of OCD. The patients underwent assessment with the Yale-Brown Obsessive-Compulsive Scale, Beck Depression Inventory, and Eating Disorder Inventory both prior to and after treatment. First, the analysis showed that the sample of OCD patients had higher prevalence of eating disorders than a population of physically active students. Moreover, the women in the sample had significantly more symptoms of eating disorders than the men. Correlational analysis showed that eating disorders did not affect the treatment outcome for OCD; the patients generally had a significant improvement of OCD symptoms. On the other hand, symptoms of eating disorders were not significantly reduced after treatment. Summarized, this study concludes that there is a high prevalence of eating disorder symptoms among patients with OCD. It further shows that comorbid eating disorders does not hinder the effect of treatment for OCD. However, as the symptoms of eating disorders persist after such treatment, an implication of the present study is that these symptoms may need closer attention.