AbstractBackgroundSurvivors of childhood acute lymphoblastic leukemia (ALL) are at risk for overweight, predisposing them to long‐term morbidity. We examined the relationship between body mass index (BMI) and demographic and lifestyle factors in a cohort of ALL survivors.ProcedureWe enrolled consecutive ALL survivors who attended the institutional AfterCare Clinic over a 1‐year period. BMI (kg/m2) at diagnosis, end‐therapy, and current time were calculated. Survivors were classified as overweight/obese (overweightgroup; BMI for age ≥85th percentile) or normal/underweight (normalweight group; BMI for age <85th percentile). We assessed the relationship between current BMI and self‐reported current caloric intake, physical activity, and sedentary behavior.Results102/157 (65%) eligible survivors consented to enrollment. Median age was 14.3 years (range 8.4–18.6) and time from end of treatment 7 years (2.5–15.6). The proportion of overweight survivors was 21%, 45%, and 35% at diagnosis, end‐therapy, and current time, respectively. The overweight group reported less calories (Δ324 kcal,P = 0.018), fat (Δ14.5 g,P = 0.02), and carbohydrates (Δ39 g,P = 0.02) than the normal weight group. These differences disappeared after excluding patients classified as under‐reporting their calorie intake according to the Goldberg cut‐off method. There were no differences in sedentary behavior or activity between groups.ConclusionsMany children with ALL gain weight during therapy and fail to return to normal weight after treatment concludes. Subsequent diet, physical activity, and sedentary behavior do not appear to differ between overweight and normal weight survivors. Clinicians should focus on ways to minimize weight gain during therapy rather than waiting for treatment to conclude. Pediatr Blood Cancer 2011; 57: 1204–1209. © 2011 Wiley Periodicals, Inc.