The assumption that liveweight increase, decrease or stasis reflects piglet response to nutritional or management strategies may be incorrect. Adjustments in tissue composition following weaning result from altered metabolic state. Such compositional changes therefore accurately describe post-weaning response but are unlikely to be detectable by measurements of piglet weight alone. Accordingly, this study evaluates the accuracy of sequential weight measurements as predictors of tissue composition determined by dissection and chemical analysis. In addition, comparisons are made between weight measurement and body density (BD) predictions of tissue characteristics.