Three greenhouse trials and one field trial were carried out on Brussels sprout cv. Icarus SG2004 in which the treatments consisted of different N amounts and application dates. DM and N accumulation in stems, apical buds and groups of leaf blades, petioles and sprouts were measured frequently throughout crop growth. Total amounts of accumulated DM and N were affected by amount of N applied and date of application, but the final harvest indexes for DM and N (0.10-0.35 and 0.20-0.55, respectively) were not significantly affected by treatments in most experiments. Nitrate N concentrations were only high (up to about 2%) shortly after planting. The total N concentration of leaf blades and petioles increased with increasing leaf number. This increase resulted from a decreasing N concentration during the leaf's life. The total N concentration in sprouts changed little with leaf number.