Background While a large number of patients with eating disorders (EDs) engage in excessive exercise (EE), both for weight control and mood regulation, there has been minimal research evaluating the relationship between EE and demographic and psychological factors, especially in adolescent patients. Purpose The goals of this study were to identify the occurrence of EE compared to other ED behaviors and to develop a regression model examining psychological, behavioral and demographic predictors of EE among adolescents with EDs. Methods Demographic and clinical information was determined for 217 adolescent patients in several levels of care (126 outpatient, 61 day program, 28 inpatient) with diagnoses of anorexia nervosa (AN) (24.9%), bulimia nervosa (BN) (25.8%), and eating disorder not otherwise specified (EDNOS) (49.3%). These patients presented to a large ED program and completed a series of questionnaires on admission to the program. Descriptive statistics, t-tests, chi-square analyses and multiple logistic regression were utilized to describe the population of adolescent patients and develop the model for predicting EE. Results Forty-seven percent of patients indicated they participated in EE in the past 4 weeks, compared to 32% for binge eating, 35% for vomiting and 15% for laxative use; 42% of patients with anorexia nervosa participated in EE, compared to 54% with bulimia nervosa and 49% with EDNOS. The regression model that was developed to predict EE, which included factors of depression, anxiety, dietary restraint, age, body mass index (BMI), diagnosis and level of care, correctly classified EE in 71.5% of cases. Dietary restraint and BMI were the two factors found to be significantly associated with EE. Conclusions Forty-seven percent of adolescent patients presenting for treatment of an ED reported participating in EE. This was larger than the numbers of patients reporting other ED behaviors that are commonly assessed, indicating the need for psychoeducation for multidisciplinary treatment teams, assessment, prevention, and clinical treatment services for this problematic behavior. It is important that those who treat patients with ED assess for and monitor EE behaviors that can complicate the treatment.