OBJECTIVE: To evaluate predictors for intervention dropout and successful reduction of metabolic syndrome risk factors among obese children enrolled in a short-term, clinic-based weight-loss intervention. DESIGN, SETTING, SUBJECTS: Retrospective database review of 1080 children 8 months-17 y.o. seen a a pediatric obesity clinic. INTERVENTIONS: Behavior modification counseling to induce change in dietary and exercise choices. MAIN OUTCOME MEASURES: 1). Pre-/post-intervention change in body mass index (BMI), waist circumference, blood pressure, glucose, insulin, and cholesterol (LDL, HDL, & total). 2) Predictors of successful decrease in BMI and clinic drop-out. ANALYSIS: Paired t-tests for pre-/post-intervention comparisons. Linear regression to assess predictors of success and predictors of drop-out, with adjustment for age, gender, race, insurance status, and service area. RESULTS: Among children evaluated, adolescent females were most likely to achieve successful decrease in BMI, insulin level, and LDL cholesterol post-intervention. Nearly 40% of children dropped out early in the intervention. Predictors of drop out included age <6y, public insurance status, follow-up scheduled during summer months, and residence in a tertiary service area. CONCLUSIONS: Clinic-based weight loss interventions can lead to successful improvements in BMI and other metabolic parameters in pediatric populations and may be more likely among adolescent females than in younger children or males. Drop-out is common, particularly among younger children, children with public insurance and children scheduled for follow-up in the summer. Identification of these drop-out predictors in individual patients may help in targeting children likely to succeed in short-term, clinic-based, weight-loss interventions.