Weight gain in children due to valproate is a major concern in the treatment of epilepsy. Previous studies have yielded conflicting results both as to how common this problem is in children and as to whether there are clinical predictors of weight gain. The authors perform a chart review of 94 pediatric patients treated with valproate to investigate weight gain and potential predictors. The slope of the regression line for the body mass index z scores for each patient at each available visit was calculated, (Deltaz-score). Relationships between Deltaz scores and predictors of interest were assessed via univariate analyses. Twenty-three of 94 patients had Deltaz score >0.25 SD/year. Twelve of 94 patients had Deltaz score >0.5 SD/year. Pediatric participants appear to be less prone to weight gain on valproate than adults. A negative correlation was found between duration on treatment and Deltaz score. No other significant correlations were found between potential clinical predictors and Deltaz score.