Boron (B) deficiency is widespread in the Anatolia region of Turkey. This could impact production and quality of Brussels sprout (Brassica oleracea L gemmifera). A 2-year field experiment was conducted to study yield and quality response of four cultivars (Star, Brilliant, Oliver, and Maximus) to B addition (0, 1, 3, and 9 kg.ha(-1) B). The optimum economic B rate (OEBR) ranged from 5.5 to 6.3 kg.ha(-1) B resulting in soil B levels of 0.94 to 1.13 mg.kg(-1). Independent of cultivar, B application decreased tissue nitrogen, calcium, and magnesium but increased tissue phosphorus, potassium, iron, manganese, zinc, and copper content. We conclude a B addition of 6 kg.ha(-1) is sufficient to elevate soil B levels to nondeficient levels. Similar studies with different soils and initial soil test B levels are needed to conclude if these critical soil test values anti OEBR can be applied across the region.