Two experiments were carried out on 48 growing Polish Landrace pigs, from 30 to 60 kg liveweight. Diets were composed of barley supplemented with rapeseed meal (RSM) or milk powder (C). Rapeseed meal contained 6.6 (RSM-7) or 24.3 µmoles (RSM-24) total glucosinolates per gram fat-free dry matter. In each experiment the animals received the same amount of metabolizable energy and lysine. Glucosinolate intake was different, however: 0 or 3.2 moles in experiment 1 and 3.2 or 10.9 moles per day in experiment 2. Energy retention in the body of animals were measured by the comparative slaughter technique. Feeding the mixture containing RSM significantly increased the weight of the liver, kidneys and thyroid. However, there were no unfavourable effects of RSM on the average daily gain and chemical body composition of the pigs. The pigs in group C produced 2.1% more heat in the body (P = 0.07) than those in group RSM-7 (Experiment 1). Increasing the glucosinolate consumption from 3.2 to 10.9 moles/day (Experiment 2) did not significantly affect heat production.