BACKGROUND: Pediatric weight management clinics experience significant dropout, and few studies have investigated this problem. The objective of this study was to identify family and clinic characteristics associated with attrition from a tertiary care pediatric weight management clinic. METHODS: This was a prospective and retrospective clinical database study of a multidisciplinary clinic for obese children 2-18 years with a weight-related co-morbidity. All patients seen between November, 2007, and July, 2009, were included. Characteristics of Active and Inactive families were compared using chi-squared and t-tests, and logistic regression was used to identify independent correlates of program status. A one-page survey was mailed to all Inactive families. RESULTS: A total of 133 patients were seen during the study period. Their mean age was 12 years old, mean BMI was 38 kg/m(2), 53% were female, 52% represented racial/ethnic minorities, and 50% were Medicaid recipients. In all, 32% dropped out of treatment. Inactive children had significantly lower BMI z-scores, were older, and were more likely to have poor school performance than active children. Similar results were found on regression analysis: Children with higher BMI z-scores, commercial insurance, average school performance, and a major weight-related co-morbidity were less likely to be inactive. The most common parent-reported reasons for dropping out were: Child not wanting to make changes, weight not improving, child desired to leave program, and program not meeting parent or child's expectations. CONCLUSIONS: Attrition from pediatric weight management treatment is high, with age, weight, school performance, and health associated with dropout. Parents mostly reported child-related issues, including lack of weight loss, as reasons for dropout.